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Author  |
Grubova, I.Y.; Surmenev, R.A.; Neyts, E.C.; Koptyug, A.V.; Volkova, A.P.; Surmeneva, M.A. |
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Title |
Combined first-principles and experimental study on the microstructure and mechanical characteristics of the multicomponent additive-manufactured Ti-35Nb-7Zr-5Ta alloy |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
ACS Omega |
Abbreviated Journal |
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Volume |
8 |
Issue |
30 |
Pages |
27519-27533 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
New & beta;-stabilizedTi-based alloys are highly promising forbone implants, thanks in part to their low elasticity. The natureof this elasticity, however, is as yet unknown. We here present combinedfirst-principles DFT calculations and experiments on the microstructure,structural stability, mechanical characteristics, and electronic structureto elucidate this origin. Our results suggest that the studied & beta;Ti-35Nb-7Zr-5Ta wt % (TNZT) alloy manufacturedby the electron-beam powder bed fusion (E-PBF) method has homogeneousmechanical properties (H = 2.01 & PLUSMN; 0.22 GPa and E = 69.48 & PLUSMN; 0.03 GPa) along the building direction,which is dictated by the crystallographic texture and microstructuremorphologies. The analysis of the structural and electronic properties,as the main factors dominating the chemical bonding mechanism, indicatesthat TNZT has a mixture of strong metallic and weak covalent bonding.Our calculations demonstrate that the softening in the Cauchy pressure(C & PRIME; = 98.00 GPa) and elastic constant C ̅ ( 44 ) = 23.84 GPa is the originof the low elasticity of TNZT. Moreover, the nature of this softeningphenomenon can be related to the weakness of the second and thirdneighbor bonds in comparison with the first neighbor bonds in theTNZT. Thus, the obtained results indicate that a carefully designedTNZT alloy can be an excellent candidate for the manufacturing oforthopedic internal fixation devices. In addition, the current findingscan be used as guidance not only for predicting the mechanical propertiesbut also the nature of elastic characteristics of the newly developedalloys with yet unknown properties. |
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Wos |
001031269000001 |
Publication Date |
2023-07-18 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2470-1343 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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no |
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Call Number |
UA @ admin @ c:irua:198313 |
Serial |
9011 |
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Author |
Grubova, I.Y.; Surmeneva, M.A.; Huygh, S.; Surmenev, R.A.; Neyts, E.C. |
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Title |
Density functional theory study of interface interactions in hydroxyapatite/rutile composites for biomedical applications |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
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Volume |
121 |
Issue |
29 |
Pages |
15687-15695 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
To gain insight into the nature of the adhesion mechanism between hydroxyapatite (HA) and rutile (rTiO(2)), the mutual affinity between their surfaces was systematically studied using density functional theory (DFT). We calculated both bulk and surface properties of HA and rTiO(2), and explored the interfacial bonding mechanism of amorphous HA (aHA) surface onto amorphous as well as stoichiometric and nonstoichiometric crystalline rTiO(2). Formation energies of bridging and subbridging oxygen vacancies considered in the rTiO(2)(110) surface were evaluated and compared with other theoretical and experimental results. The interfacial interaction was evaluated through the work of adhesion. For the aHA/rTiO(2)(110) interfaces, the work of adhesion is found to depend strongly on the chemical environment of the rTiO(2)(110) surface. Electronic analysis indicates that the charge transfer is very small in the case of interface formation between aHA and crystalline rTiO(2)(110). In contrast, significant charge transfer occurs between aHA and amorphous rTiO(2) (aTiO(2)) slabs during the formation of the interface. Charge density difference (CDD) analysis indicates that the dominant interactions in the interface have significant covalent character, and in particular the Ti-O and Ca-O bonds. Thus, the obtained results reveal that the aHA/aTiO(2) interface shows a more preferable interaction and is thermodynamically more stable than other interfaces. These results are particularly important for improving the long-term stability of HA-based implants. |
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Place of Publication |
Washington, D.C. |
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Wos |
000406726200022 |
Publication Date |
2017-06-27 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1932-7447; 1932-7455 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.536 |
Times cited |
5 |
Open Access |
Not_Open_Access |
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Notes |
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Approved |
Most recent IF: 4.536 |
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Call Number |
UA @ lucian @ c:irua:145195 |
Serial |
4715 |
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Author |
Grubova, I.Y.; Surmeneva, M.A.; Huygh, S.; Surmenev, R.A.; Neyts, E.C. |
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Title |
Effects of silicon doping on strengthening adhesion at the interface of the hydroxyapatite-titanium biocomposite : a first-principles study |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
Computational materials science |
Abbreviated Journal |
Comp Mater Sci |
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Volume |
159 |
Issue |
159 |
Pages |
228-234 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
In this paper we employ first-principles calculations to investigate the effect of substitutional Si doping in the amorphous calcium-phosphate (a-HAP) structure on the work of adhesion, integral charge transfer, charge density difference and theoretical tensile strengths between an a-HAP coating and amorphous titanium dioxide (a-TiO2) substrate systemically. Our calculations demonstrate that substitution of a P atom by a Si atom in a-HAP (a-Si-HAP) with the creation of OH-vacancies as charge compensation results in a significant increase of the bonding strength of the coating to the substrate. The work of adhesion of the optimized Si-doped interfaces reaches a value of up to -2.52 J m(-2), which is significantly higher than for the stoichiometric a-HAP/a-TiO2. Charge density difference analysis indicates that the dominant interactions at the interface have significant covalent character, and in particular two Ti-O and three Ca-O bonds are formed for a-Si-HAP/a-TiO2 and one Ti-O and three Ca-O bonds for a-HAP/a-TiO2. From the stress-strain curve, the Young's modulus of a-Si-HAP/a-TiO2 is calculated to be about 25% higher than that of the a-HAP/a-TiO2, and the yielding stress is about 2 times greater than that of the undoped model. Our calculations therefore demonstrate that the presence of Si in the a-HAP structure strongly alters not only the bioactivity and resorption rates, but also the mechanical properties of the a-HAP/a-TiO2 interface. The results presented here provide an important theoretical insight into the nature of the chemical bonding at the a-HAP/a-TiO2 interface, and are particularly significant for the practical medical applications of HAP-based biomaterials. |
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Wos |
000457856900023 |
Publication Date |
2018-12-18 |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0927-0256 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.292 |
Times cited |
1 |
Open Access |
Not_Open_Access |
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Notes |
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Approved |
Most recent IF: 2.292 |
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Call Number |
UA @ admin @ c:irua:157480 |
Serial |
5272 |
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Author |
Grubova, I.Y.; Surmeneva, M.A.; Surmenev, R.A.; Neyts, E.C. |
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Title |
Effect of van der Waals interactions on the adhesion strength at the interface of the hydroxyapatite-titanium biocomposite : a first-principles study |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
RSC advances |
Abbreviated Journal |
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Volume |
10 |
Issue |
62 |
Pages |
37800-37805 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
Hydroxyapatite (HAP) is frequently used as biocompatible coating on Ti-based implants. In this context, the HAP-Ti adhesion is of crucial importance. Here, we report ab initio calculations to investigate the influence of Si incorporation into the amorphous calcium-phosphate (a-HAP) structure on the interfacial bonding mechanism between the a-HAP coating and an amorphous titanium dioxide (a-TiO2) substrate, contrasting two different density functionals: PBE-GGA, and DFT-D3, which are capable of describing the influence of the van der Waals (vdW) interactions. In particular, we discuss the effect of dispersion on the work of adhesion (W-ad), equilibrium geometries, and charge density difference (CDD). We find that replacement of P by Si in a-HAP (a-Si-HAP) with the creation of OH vacancies as charge compensation results in a significant increase in the bond strength between the coating and substrate in the case of using the PBE-GGA functional. However, including the vdW interactions shows that these forces considerably contribute to the W-ad. We show that the difference (W-ad – W-ad(vdW)) is on average more than 1.1 J m(-2) and 0.5 J m(-2) for a-HAP/a-TiO2 and a-Si-HAP/a-TiO2, respectively. These results reveal that including vdW interactions is essential for accurately describing the chemical bonding at the a-HAP/a-TiO2 interface. |
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Wos |
000583523300025 |
Publication Date |
2020-10-14 |
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UA library record; WoS full record; WoS citing articles |
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Times cited |
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Notes |
; The authors gratefully acknowledge financial support from the Russian president's grant MK-330.2020.8 and BOF Fellowships for International Joint PhD students funded by University of Antwerp (UAntwerp, project number 32545). The work was carried out at Tomsk Polytechnic University within the framework of Tomsk Polytechnic University Competitiveness Enhancement Program grant and in part using the Turing HPC infrastructure of the CalcUA core facility of the UAntwerp, a division of the Flemish Supercomputer Centre (VSC), funded by the Hercules Foundation, the Flemish Government (department EWI) and the UAntwerp, Belgium. ; |
Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:173603 |
Serial |
6499 |
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Author |
Heyne, M.H.; de Marneffe, J.-F.; Delabie, A.; Caymax, M.; Neyts, E.C.; Radu, I.; Huyghebaert, C.; De Gendt, S. |
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Title |
Two-dimensional WS2 nanoribbon deposition by conversion of pre-patterned amorphous silicon |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Nanotechnology |
Abbreviated Journal |
Nanotechnology |
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Volume |
28 |
Issue |
28 |
Pages |
04LT01 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
We present a method for area selective deposition of 2D WS2 nanoribbons with tunable thickness on a dielectric substrate. The process is based on a complete conversion of a prepatterned, H-terminated Si layer to metallic W by WF6, followed by in situ sulfidation by H2S. The reaction process, performed at 450 degrees C, yields nanoribbons with lateral dimension down to 20 nm and with random basal plane orientation. The thickness of the nanoribbons is accurately controlled by the thickness of the pre-deposited Si layer. Upon rapid thermal annealing at 900 degrees C under inert gas, the WS2 basal planes align parallel to the substrate. |
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Corporate Author |
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Publisher |
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Place of Publication |
Bristol |
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Language |
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Wos |
000391445100001 |
Publication Date |
2016-12-15 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0957-4484 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.44 |
Times cited |
13 |
Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 3.44 |
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Call Number |
UA @ lucian @ c:irua:140382 |
Serial |
4471 |
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Author |
Heyne, M.H.; de Marneffe, J.-F.; Nuytten, T.; Meersschaut, J.; Conard, T.; Caymax, M.; Radu, I.; Delabie, A.; Neyts, E.C.; De Gendt, S. |
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Title |
The conversion mechanism of amorphous silicon to stoichiometric WS2 |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Journal of materials chemistry C : materials for optical and electronic devices |
Abbreviated Journal |
J Mater Chem C |
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Volume |
6 |
Issue |
15 |
Pages |
4122-4130 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
The deposition of ultra-thin tungsten films and their related 2D chalcogen compounds on large area dielectric substrates by gas phase reactions is challenging. The lack of nucleation sites complicates the adsorption of W-related precursors and subsequent sulfurization usually requires high temperatures. We propose here a technique in which a thin solid amorphous silicon film is used as reductant for the gas phase precursor WF6 leading to the conversion to metallic W. The selectivity of the W conversion towards the underlying dielectric surfaces is demonstrated. The role of the Si surface preparation, the conversion temperature, and Si thickness on the formation process is investigated. Further, the in situ conversion of the metallic tungsten into thin stoichiometric WS2 is achieved by a cyclic approach based on WF6 and H2S pulses at the moderate temperature of 450 1C, which is much lower than usual oxide sulfurization processes. |
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Place of Publication |
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Wos |
000430538000036 |
Publication Date |
2018-03-20 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2050-7526 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
5.256 |
Times cited |
4 |
Open Access |
OpenAccess |
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Notes |
This work was supported throughout a strategic fundamental research grant for M. H. by the agency Flanders innovation & entrepreneurship (VLAIO). |
Approved |
Most recent IF: 5.256 |
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Call Number |
PLASMANT @ plasmant @c:irua:150968 |
Serial |
4921 |
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Author |
Heyne, M.H.; de Marneffe, J.-F.; Radu, I.; Neyts, E.C.; De Gendt, S. |
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Title |
Thermal recrystallization of short-range ordered WS2 films |
Type |
A1 Journal article |
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Year |
2018 |
Publication |
Journal of vacuum science and technology: A: vacuum surfaces and films |
Abbreviated Journal |
J Vac Sci Technol A |
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Volume |
36 |
Issue |
5 |
Pages |
05g501 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
The integration of van der Waals materials in nanoelectronic devices requires the deposition of few-layered MX2 films with excellent quality crystals covering a large area. In recent years, astonishing progress in the monolayer growth of WS2 and MoS2 was demonstrated, but multilayer growth resulted often in separated triangular or hexagonal islands. These polycrystalline films cannot fully employ the specific MX2 properties since they are not connected in-plane to the other domains. To coalesce separated islands, ultrahigh-temperature postdeposition anneals in H2S are applied, which are not compatible with bare silicon substrates. Starting from the deposition of stoichiometric short-ordered films, the present work studies different options for subsequent high-temperature annealing in an inert atmosphere to form crystalline films with large grains from stoichiometric films with small grains. The rapid thermal annealing, performed over a few seconds, is compared to excimer laser annealing in the nanosecond range, which are both able to crystallize the thin WS2. The WS2 recrystallization temperature can be lowered using metallic crystallization promoters (Co and Ni). The best result is obtained using a Co cap, due to the circumvention of Co and S binary phase formation below the eutectic temperature. The recrystallization above a critical temperature is accompanied by sulfur loss and 3D regrowth. These undesired effects can be suppressed by the application of a dielectric capping layer prior to annealing. A SiO2 cap can suppress the sulfur loss successfully during annealing and reveals improved material quality in comparison to noncapped films Published by the AVS. |
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Place of Publication |
New York, N.Y. |
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Wos |
000444033200002 |
Publication Date |
2018-07-05 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0734-2101 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.374 |
Times cited |
2 |
Open Access |
Not_Open_Access |
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Notes |
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Approved |
Most recent IF: 1.374 |
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Call Number |
UA @ lucian @ c:irua:153671 |
Serial |
5134 |
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Author |
Heyne, M.H.; Marinov, D.; Braithwaite, N.; Goodyear, A.; de Marneffe, J.-F.; Cooke, M.; Radu, I.; Neyts, E.C.; De Gendt, S. |
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Title |
A route towards the fabrication of 2D heterostructures using atomic layer etching combined with selective conversion |
Type |
A1 Journal article |
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Year |
2019 |
Publication |
2D materials |
Abbreviated Journal |
2D Mater |
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Volume |
6 |
Issue |
3 |
Pages |
035030 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
Heterostructures of low-dimensional semiconducting materials, such as transition metal dichalcogenides (MX2), are promising building blocks for future electronic and optoelectronic devices. The patterning of one MX2 material on top of another one is challenging due to their structural similarity. This prevents an intrinsic etch stop when conventional anisotropic dry etching processes are used. An alternative approach consist in a two-step process, where a sacrificial silicon layer is pre-patterned with a low damage plasma process, stopping on the underlying MoS2 film. The pre-patterned layer is used as sacrificial template for the formation of the top WS2 film. This study describes the optimization of a cyclic Ar/Cl-2 atomic layer etch process applied to etch silicon on top of MoS2, with minimal damage, followed by a selective conversion of the patterned Si into WS2. The impact of the Si atomic layer etch towards the MoS2 is evaluated: in the ion energy range used for this study, MoS2 removal occurs in the over-etch step over 1-2 layers, leading to the appearance of MoOx but without significant lattice distortions to the remaining layers. The combination of Si atomic layer etch, on top of MoS2, and subsequent Si-to-WS2 selective conversion, allows to create a WS2/MoS2 heterostructure, with clear Raman signals and horizontal lattice alignment. These results demonstrate a scalable, transfer free method to achieve horizontally individually patterned heterostacks and open the route towards wafer-level processing of 2D materials. |
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Place of Publication |
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Wos |
000468335500004 |
Publication Date |
2019-04-23 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2053-1583 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.937 |
Times cited |
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Open Access |
Not_Open_Access |
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Notes |
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Approved |
Most recent IF: 6.937 |
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Call Number |
UA @ admin @ c:irua:160229 |
Serial |
5266 |
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Author |
Huygh, S.; Bogaerts, A.; Bal, K.M.; Neyts, E.C. |
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Title |
High Coke Resistance of a TiO2Anatase (001) Catalyst Surface during Dry Reforming of Methane |
Type |
A1 Journal Article |
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Year |
2018 |
Publication |
Journal Of Physical Chemistry C |
Abbreviated Journal |
J Phys Chem C |
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Volume |
122 |
Issue |
17 |
Pages |
9389-9396 |
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Keywords |
A1 Journal Article; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ; |
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Abstract |
The resistance of a TiO2 anatase (001) surface to coke formation was studied in the context of dry reforming of methane using density functional theory (DFT) calculations. As carbon atoms act as precursors for coke formation, the resistance to coke formation can be measured by the carbon coverage of the surface. This is related to the stability of different CHx (x = 0−3) species and their rate of hydrogenation and dehydrogenation on the TiO2 surface. Therefore, we studied the reaction mechanisms and their corresponding rates as a function of the temperature for the dehydrogenation of the species on the surface. We found that the stabilities of C and CH are significantly lower than those of CH3 and CH2. The hydrogenation rates of the different species are significantly higher than the dehydrogenation rates in a temperature range of 300−1000 K. Furthermore, we found that dehydrogenation of CH3, CH2, and CH will only occur at appreciable rates starting from 600, 900, and 900 K, respectively. On the basis of these results, it is clear that the anatase (001) surface has a high coke resistance, and it is thus not likely that the surface will become poisoned by coke during dry reforming of methane. As the rate limiting step in dry reforming is the dissociative adsorption of CH4, we studied an alternative approach to thermal catalysis. We found that the temperature threshold for dry reforming is at least 700 K. This threshold temperature may be lowered by the use of plasma-catalysis, where the appreciable rates of adsorption of plasma-generated CHx radicals result in bypassing the rate limiting step of the reaction. |
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Place of Publication |
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Wos |
000431723700014 |
Publication Date |
2018-05-03 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1932-7447 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.536 |
Times cited |
1 |
Open Access |
OpenAccess |
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Notes |
Federaal Wetenschapsbeleid, IAP/7 ; Fonds Wetenschappelijk Onderzoek, G.0217.14N ; Onderzoeksfonds, Universiteit Antwerpen, 32249 ; |
Approved |
Most recent IF: 4.536 |
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Call Number |
PLASMANT @ plasmant @c:irua:151529c:irua:152816 |
Serial |
5000 |
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| Permanent link to this record |
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Author |
Huygh, S.; Bogaerts, A.; Neyts, E.C. |
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Title |
How Oxygen Vacancies Activate CO2 Dissociation on TiO2 Anatase (001) |
Type |
A1 Journal article |
| |
Year |
2016 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
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| |
Volume |
120 |
Issue |
120 |
Pages |
21659-21669 |
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| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
The adsorption, dissociation, and diffusion of CO2 on the anatase (001) surface was studied using DFT by means of the generalized gradient approximation using the Perdew−Burcke−Ernzerhof (PBE)-functional and applying corrections for long-range dispersion interactions. Different stable adsorption configurations were identified for the fully oxidized surface. The most stable adsorption configuration is the monodentated carbonate-like structure. Small energy barriers were identified for the conversion of a physisorbed to a chemisorbed configuration.
CO2 dissociation is found to be unfeasible on the stoichiometric surface. The introduction of oxygen vacancy defects gives rise to new highly stable adsorption configurations with a stronger activation of the C−O bonds. This leads to the possibility of exothermic dissociation of CO2 with barriers up to 22.2 kcal/mol,
corresponding to chemical lifetimes of less than 4 s at 300 K. These reactions cause a CO molecule to be formed, which will easily desorb, and the reduced surface to become oxidized. It is clear that oxygen vacancy defects play a key role in the catalytic activity of an anatase (001) surface. Oxygen vacancies play an important role in the dissociation of CO2 on the anatase (001) surface, and will play a significant role in complex problems, such as the catalytic conversion of CO2 to value-added chemicals. |
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Corporate Author |
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Thesis |
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Place of Publication |
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Editor |
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Language |
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Wos |
000384626800055 |
Publication Date |
2016-09-02 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
1932-7447 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
4.536 |
Times cited |
49 |
Open Access |
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| |
Notes |
Stijn Huygh is funded as an aspirant of the Research Foundation Flanders (FWO, project number 11C0115N). This work was carried out using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen (UAntwerpen), a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI), and the UAntwerpen. |
Approved |
Most recent IF: 4.536 |
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| |
Call Number |
PLASMANT @ plasmant @ c:irua:136164 |
Serial |
4291 |
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| Permanent link to this record |
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Author |
Huygh, S.; Bogaerts, A.; van Duin, A.C.T.; Neyts, E.C. |
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| |
Title |
Development of a ReaxFF reactive force field for intrinsic point defects in titanium dioxide |
Type |
A1 Journal article |
| |
Year |
2014 |
Publication |
Computational materials science |
Abbreviated Journal |
Comp Mater Sci |
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| |
Volume |
95 |
Issue |
|
Pages |
579-591 |
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| |
Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
A reactive ReaxFF force field is developed for studying the influence of intrinsic point defects on the chemistry with TiO2 condensed phases. The force field parameters are optimized to ab initio data for the equations of state, relative phase stabilities for titanium and titanium dioxide, potential energy differences for (TiO2)n-clusters (n = 116). Also data for intrinsic point defects in anatase were added. These data contain formation energies for interstitial titanium and oxygen vacancies, diffusion barriers of the oxygen vacancies and molecular oxygen adsorption on a reduced anatase (101) surface. Employing the resulting force field, we study the influence of concentration of oxygen vacancies and expansion or compression of an anatase surface on the diffusion of the oxygen vacancies. Also the barrier for oxygen diffusion in the subsurface region is evaluated using this force field. This diffusion barrier of 27.7 kcal/mol indicates that the lateral redistribution of oxygen vacancies on the surface and in the subsurface will be dominated by their diffusion in the subsurface, since both this barrier as well as the barriers for diffusion from the surface to the subsurface and vice versa (17.07 kcal/mol and 21.91 kcal/mol, respectively, as calculated with DFT), are significantly lower than for diffusion on the surface (61.12 kcal/mol as calculated with DFT). |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000343781700077 |
Publication Date |
2014-09-16 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
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| |
ISSN |
0927-0256; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
2.292 |
Times cited |
15 |
Open Access |
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Notes |
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Approved |
Most recent IF: 2.292; 2014 IF: 2.131 |
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| |
Call Number |
UA @ lucian @ c:irua:119409 |
Serial |
682 |
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| Permanent link to this record |
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Author |
Huygh, S.; Neyts, E.C. |
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Title |
Adsorption of C and CHx radicals on anatase (001) and the influence of oxygen vacancies |
Type |
A1 Journal article |
| |
Year |
2015 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
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| |
Volume |
119 |
Issue |
119 |
Pages |
4908-4921 |
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| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
The adsorption of C and CHx radicals on anatase (001) was studied using DFT within the generalized gradient approximation using the Perde-Burke-Ernzerhof (PBE) functional. We have studied the influence of oxygen vacancies in and at the surface on the adsorption properties of the radicals. For the oxygen vacancies in anatase (001), the most stable vacancy is located at the surface. For this vacancy, the maximal adsorption strength of C and CH decreases compared to the adsorption on the stoichiometric surface, but it increases for CH2 and CH3. If an oxygen vacancy is present in the first subsurface layer, the maximal adsorption strength increases for C, CH, CH2, and CH3. When the vacancy is present in the next subsurface layer, we find that only the CH3 adsorption is enhanced, while the maximal adsorption energies for the other radical species decrease. Not only does the precise location of the oxygen vacancy determine the maximal adsorption interaction, it also influences the adsorption strengths of the radicals at different surface configurations. This determines the probability of finding a certain adsorption configuration at the surface, which in turn influences the possible surface reactions. We find that C preferentially adsorbs far away from the oxygen vacancy, while CH2 and CH3 adsorb preferentially at the oxygen vacancy site. A fraction of CH partially adsorbs at the oxygen vacancy, and another fraction adsorbs further away from the vacancy. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000350840700052 |
Publication Date |
2015-02-18 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1932-7447;1932-7455; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
4.536 |
Times cited |
13 |
Open Access |
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Notes |
|
Approved |
Most recent IF: 4.536; 2015 IF: 4.772 |
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Call Number |
c:irua:124909 |
Serial |
63 |
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| Permanent link to this record |
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Author |
Izadi, M.E.; Bal, K.M.; Maghari, A.; Neyts, E.C. |
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Title |
Reaction mechanisms of C(3PJ) and C+(2PJ) with benzene in the interstellar medium from quantum mechanical molecular dynamics simulations |
Type |
A1 Journal article |
| |
Year |
2021 |
Publication |
Physical Chemistry Chemical Physics |
Abbreviated Journal |
Phys Chem Chem Phys |
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| |
Volume |
23 |
Issue |
7 |
Pages |
4205-4216 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
While spectroscopic data on small hydrocarbons in interstellar media in combination with crossed molecular beam (CMB) experiments have provided a wealth of information on astrochemically relevant species, much of the underlying mechanistic pathways of their formation remain elusive. Therefore, in this work, the chemical reaction mechanisms of C(<sup>3</sup>P<sub>J</sub>) + C<sub>6</sub>H<sub>6</sub>and C<sup>+</sup>(<sup>2</sup>P) + C<sub>6</sub>H<sub>6</sub>systems using the quantum mechanical molecular dynamics (QMMD) technique at the PBE0-D3(BJ) level of theory is investigated, mimicking a CMB experiment. Both the dynamics of the reactions as well as the electronic structure for the purpose of the reaction network are evaluated. The method is validated for the first reaction by comparison to the available experimental data. The reaction scheme for the C(<sup>3</sup>P<sub>J</sub>) + C<sub>6</sub>H<sub>6</sub>system covers the literature data,<italic>e.g.</italic>the major products are the 1,2-didehydrocycloheptatrienyl radical (C<sub>7</sub>H<sub>5</sub>) and benzocyclopropenyl radical (C<sub>6</sub>H<sub>5</sub>–CH), and it reveals the existence of less common pathways for the first time. The chemistry of the C<sup>+</sup>(<sup>2</sup>P<sub>J</sub>) + C<sub>6</sub>H<sub>6</sub>system is found to be much richer, and we have found that this is because of more exothermic reactions in this system in comparison to those in the C(<sup>3</sup>P<sub>J</sub>) + C<sub>6</sub>H<sub>6</sub>system. Moreover, using the QMMD simulation, a number of reaction paths have been revealed that produce three distinct classes of reaction products with different ring sizes. All in all, at all the collision energies and orientations, the major product is the heptagon molecular ion for the ionic system. It is also revealed that the collision orientation has a dominant effect on the reaction products in both systems, while the collision energy mostly affects the charged system. These simulations both prove the applicability of this approach to simulate crossed molecular beams, and provide fundamental information on reactions relevant for the interstellar medium. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
000621595300016 |
Publication Date |
2021-01-18 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1463-9076 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.123 |
Times cited |
|
Open Access |
OpenAccess |
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Notes |
Fonds Wetenschappelijk Onderzoek, 12ZI420N ; Ministry of Science Research and Technology; Universiteit Antwerpen; The financial support from the Iran Ministry of Science, Research and Technology and PLASMANT Research Group University of Antwerp is highly acknowledged by the authors. K.M.B. was funded as a junior postdoctoral fellow of the FWO (Research Foundation – Flanders), Grant 12ZI420N. The computational resources and services used in this work were provided by the HPC core facility CalcUA of the Universiteit Antwerpen, and VSC (Flemish Supercomputer Center), funded by the FWO and the Flemish Government. |
Approved |
Most recent IF: 4.123 |
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| |
Call Number |
PLASMANT @ plasmant @c:irua:176672 |
Serial |
6742 |
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| Permanent link to this record |
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Author |
Jafarzadeh, A.; Bal, K.M.; Bogaerts, A.; Neyts, E.C. |
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Title |
CO2 activation on TiO2-supported Cu5 and Ni5 nanoclusters : effect of plasma-induced surface charging |
Type |
A1 Journal article |
| |
Year |
2019 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
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Volume |
123 |
Issue |
11 |
Pages |
6516-6525 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
Surface charging is an often overlooked factor in many plasma-surface interactions and in particular in plasma catalysis. In this study, we investigate the effect of excess electrons induced by a plasma on the adsorption properties of CO2 on titania-supported Cu-5 and Ni-5 clusters using spin-polarized and dispersion-corrected density functional theory calculations. The effect of excess electrons on the adsorption of Ni and Cu pentamers as well as on CO2 adsorption on a pristine anatase TiO2(101) slab is studied. Our results indicate that adding plasma-induced excess electrons to the system leads to further stabilization of the bent CO2 structure. Also, dissociation of CO2 on charged clusters is energetically more favorable than on neutral clusters. We hypothesize that surface charge is a plausible cause for the synergistic effects sometimes observed in plasma catalysis. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000462260700024 |
Publication Date |
2019-02-21 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1932-7447; 1932-7455 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
4.536 |
Times cited |
4 |
Open Access |
OpenAccess |
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Notes |
|
Approved |
Most recent IF: 4.536 |
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Call Number |
UA @ admin @ c:irua:159422 |
Serial |
5281 |
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| Permanent link to this record |
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Author |
Jafarzadeh, A.; Bal, K.M.; Bogaerts, A.; Neyts, E.C. |
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Title |
Activation of CO2on Copper Surfaces: The Synergy between Electric Field, Surface Morphology, and Excess Electrons |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Journal Of Physical Chemistry C |
Abbreviated Journal |
J Phys Chem C |
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Volume |
124 |
Issue |
12 |
Pages |
6747-6755 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
In this work, we use density functional theory calculations to study the combined effect of external electric fields, surface morphology, and surface charge on CO2 activation over Cu(111), Cu(211), Cu(110), and Cu(001) surfaces. We observe that the binding energy of the CO2 molecule on Cu surfaces increases significantly upon increasing the applied electric field strength. In addition, rougher surfaces respond more effectively to the presence of the external electric field toward facilitating the formation of a carbonate-like CO2 structure and the transformation of the most stable adsorption mode from physisorption to chemisorption. The presence of surface charges further strengthens the electric field effect and consequently causes an improved bending of the CO2 molecule and C−O bond length elongation. On the other hand, a net charge in the absence of an externally applied electric field shows only a marginal effect on CO2 binding. The chemisorbed CO2 is more stable and further activated when the effects of an external electric field, rough surface, and surface charge are combined. These results can help to elucidate the underlying factors that control CO2 activation in heterogeneous and plasma catalysis, as well as in electrochemical processes. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000526396900030 |
Publication Date |
2020-03-26 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1932-7447 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.7 |
Times cited |
|
Open Access |
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Notes |
Bijzonder Onderzoeksfonds, 32249 ; The financial support from the TOP research project of the Research Fund of the University of Antwerp (grant ID: 32249) is highly acknowledged by the authors. The computational resources used in this study were provided by the VSC (Flemish Supercomputer Center), funded by the FWO and the Flemish Governmentdepartment EWI. |
Approved |
Most recent IF: 3.7; 2020 IF: 4.536 |
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Call Number |
PLASMANT @ plasmant @c:irua:168606 |
Serial |
6361 |
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Author |
Javdani, Z.; Hassani, N.; Faraji, F.; Zhou, R.; Sun, C.; Radha, B.; Neyts, E.; Peeters, F.M.; Neek-Amal, M. |
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Title |
Clogging and unclogging of hydrocarbon-contaminated nanochannels |
Type |
A1 Journal article |
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Year |
2022 |
Publication |
The journal of physical chemistry letters |
Abbreviated Journal |
J Phys Chem Lett |
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Volume |
13 |
Issue |
49 |
Pages |
11454-11463 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
The recent advantages of the fabrication of artificial nanochannels enabled new research on the molecular transport, permeance, and selectivity of various gases and molecules. However, the physisorption/chemisorption of the unwanted molecules (usually hydrocarbons) inside nanochannels results in the alteration of the functionality of the nanochannels. We investigated contamination due to hydrocarbon molecules, nanochannels made of graphene, hexagonal boron nitride, BC2N, and molybdenum disulfide using molecular dynamics simulations. We found that for a certain size of nanochannel (i.e., h = 0.7 nm), as a result of the anomalous hydrophilic nature of nanochannels made of graphene, the hydrocarbons are fully adsorbed in the nanochannel, giving rise to full uptake. An increasing temperature plays an important role in unclogging, while pressure does not have a significant role. The results of our pioneering work contribute to a better understanding and highlight the important factors in alleviating the contamination and unclogging of nanochannels, which are in good agreement with the results of recent experiments. |
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Corporate Author |
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Thesis |
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Place of Publication |
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Editor |
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Language |
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Wos |
000893147700001 |
Publication Date |
2022-12-05 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1948-7185 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
5.7 |
Times cited |
|
Open Access |
OpenAccess |
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Notes |
|
Approved |
Most recent IF: 5.7 |
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Call Number |
UA @ admin @ c:irua:192815 |
Serial |
7263 |
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Author |
Kato, T.; Neyts, E.C.; Abiko, Y.; Akama, T.; Hatakeyama, R.; Kaneko, T. |
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Title |
Kinetics of energy selective Cs encapsulation in single-walled carbon nanotubes for damage-free and position-selective doping |
Type |
A1 Journal article |
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Year |
2015 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
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Volume |
119 |
Issue |
119 |
Pages |
11903-11908 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
A method has been developed for damage-free cesium (Cs) encapsulation within single-walled carbon nanotubes (SWNTs) with fine position selectivity. Precise energy tuning of Cs-ion irradiation revealed that there is a clear energy window (2060 eV) for the efficient encapsulation of Cs through the hexagonal network of SWNT sidewalls without causing significant damage. This minimum energy threshold of Cs-ion encapsulation (∼20 eV) matches well with the value obtained by ab initio simulation (∼22 eV). Furthermore, position-selective Cs encapsulation was carried out, resulting in the successful formation of pn-junction SWNT thin films with excellent environmental stability. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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Language |
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Wos |
000355495600072 |
Publication Date |
2015-05-06 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1932-7447;1932-7455; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.536 |
Times cited |
3 |
Open Access |
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Notes |
|
Approved |
Most recent IF: 4.536; 2015 IF: 4.772 |
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Call Number |
c:irua:125928 |
Serial |
1760 |
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| Permanent link to this record |
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Author |
Khalilov, U.; Bogaerts, A.; Hussain, S.; Kovacevic, E.; Brault, P.; Boulmer-Leborgne, C.; Neyts, E.C. |
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Title |
Nanoscale mechanisms of CNT growth and etching in plasma environment |
Type |
A1 Journal article |
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Year |
2017 |
Publication |
Journal of physics: D: applied physics |
Abbreviated Journal |
J Phys D Appl Phys |
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Volume |
50 |
Issue |
50 |
Pages |
184001 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
Plasma-enhanced chemical deposition (PECVD) of carbon nanotubes has already been shown to allow chirality control to some extent. In PECVD, however, etching may occur simultaneously with the growth, and the occurrence of intermediate processes further significantly complicates the growth process.
We here employ a computational approach with experimental support to study the plasma-based formation of Ni nanoclusters, Ni-catalyzed CNT growth and subsequent etching processes, in order to understand the underpinning nanoscale mechanisms. We find that hydrogen is the dominant factor in both the re-structuring of a Ni film and the subsequent appearance of Ni nanoclusters, as well as in the CNT nucleation and etching processes. The obtained results are compared with available theoretical and experimental studies and provide a deeper understanding of the occurring nanoscale mechanisms in plasma-assisted CNT nucleation and growth. |
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Corporate Author |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000398300900001 |
Publication Date |
2017-04-03 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0022-3727 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.588 |
Times cited |
6 |
Open Access |
OpenAccess |
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Notes |
UK gratefully acknowledges financial support from the Research Foundation – Flanders (FWO), Belgium (Grant No. 12M1315N). The work was carried out in part using the Turing HPC infrastructure of the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Centre VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the Universiteit Antwerpen. The authors also thank Prof A C T van Duin for sharing the ReaxFF code. |
Approved |
Most recent IF: 2.588 |
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Call Number |
PLASMANT @ plasmant @ c:irua:141918 |
Serial |
4533 |
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| Permanent link to this record |
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Author |
Khalilov, U.; Bogaerts, A.; Neyts, E.C. |
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Title |
Microscopic mechanisms of vertical graphene and carbon nanotube cap nucleation from hydrocarbon growth precursors |
Type |
A1 Journal article |
| |
Year |
2014 |
Publication |
Nanoscale |
Abbreviated Journal |
Nanoscale |
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| |
Volume |
6 |
Issue |
15 |
Pages |
9206-9214 |
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| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
|
| |
Abstract |
Controlling and steering the growth of single walled carbon nanotubes is often believed to require controlling of the nucleation stage. Yet, little is known about the microscopic mechanisms governing the nucleation from hydrocarbon molecules. Specifically, we address here the dehydrogenation of hydrocarbon molecules and the formation of all-carbon graphitic islands on metallic nanoclusters from hydrocarbon molecules under conditions typical for carbon nanotube growth. Employing reactive molecular dynamics simulations, we demonstrate for the first time that the formation of a graphitic network occurs through the intermediate formation of vertically oriented, not fully dehydrogenated graphitic islands. Upon dehydrogenation of these vertical graphenes, the islands curve over the surface, thereby forming a carbon network covering the nanoparticle. The results indicate that controlling the extent of dehydrogenation offers an additional parameter to control the nucleation of carbon nanotubes. |
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| |
Address |
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Corporate Author |
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Thesis |
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|
| |
Publisher |
|
Place of Publication |
Cambridge |
Editor |
|
|
| |
Language |
|
Wos |
000339861500103 |
Publication Date |
2014-05-27 |
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2040-3364;2040-3372; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
7.367 |
Times cited |
21 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 7.367; 2014 IF: 7.394 |
|
| |
Call Number |
UA @ lucian @ c:irua:117950 |
Serial |
2027 |
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| Permanent link to this record |
| |
|
| |
|
Author |
Khalilov, U.; Bogaerts, A.; Neyts, E.C. |
|
| |
Title |
Atomic scale simulation of carbon nanotube nucleation from hydrocarbon precursors |
Type |
A1 Journal article |
| |
Year |
2015 |
Publication |
Nature communications |
Abbreviated Journal |
Nat Commun |
|
| |
Volume |
6 |
Issue |
6 |
Pages |
10306 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
|
| |
Abstract |
Atomic scale simulations of the nucleation and growth of carbon nanotubes is essential for understanding their growth mechanism. In spite of over twenty years of simulation efforts in this area, limited progress has so far been made on addressing the role of the hydrocarbon growth precursor. Here we report on atomic scale simulations of cap nucleation of single-walled carbon nanotubes from hydrocarbon precursors. The presented mechanism emphasizes the important role of hydrogen in the nucleation process, and is discussed in relation to previously presented mechanisms. In particular, the role of hydrogen in the appearance of unstable carbon structures during in situ experimental observations as well as the initial stage of multi-walled carbon nanotube growth is discussed. The results are in good agreement with available experimental and quantum-mechanical results, and provide a basic understanding of the incubation and nucleation stages of hydrocarbon-based CNT growth at the atomic level. |
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| |
Address |
PLASMANT research group, Department of Chemistry, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium |
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| |
Corporate Author |
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Thesis |
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| |
Publisher |
|
Place of Publication |
|
Editor |
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|
| |
Language |
English |
Wos |
000367584500001 |
Publication Date |
2015-12-22 |
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| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2041-1723 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
12.124 |
Times cited |
37 |
Open Access |
|
|
| |
Notes |
The authors gratefully acknowledge financial support from the Fund of Scientific Research Flanders (FWO), Belgium, grant number 12M1315N. The work was carried out in part using the Turing HPC infrastructure of the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Centre VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the Universiteit Antwerpen. We thank Professor Adri C. T. van Duin for sharing the ReaxFF code. |
Approved |
Most recent IF: 12.124; 2015 IF: 11.470 |
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| |
Call Number |
c:irua:129975 |
Serial |
3990 |
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| Permanent link to this record |
| |
|
| |
|
Author |
Khalilov, U.; Bogaerts, A.; Neyts, E.C. |
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| |
Title |
Atomic-scale mechanisms of plasma-assisted elimination of nascent base-grown carbon nanotubes |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Carbon |
Abbreviated Journal |
Carbon |
|
| |
Volume |
118 |
Issue |
118 |
Pages |
452-457 |
|
| |
Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
|
| |
Abstract |
Selective etching allows for obtaining carbon nanotubes with a specific chirality. While plasma-assisted etching has already been used to separate metallic tubes from their semiconducting counterparts, little is known about the nanoscale mechanisms of the etching process. We combine (reactive) molecular dynamics (MD) and force-bias Monte Carlo (tfMC) simulations to study H-etching of CNTs. In particular, during the hydrogenation and subsequent etching of both the carbon cap and the tube, they sequentially transform to different carbon nanostructures, including carbon nanosheet, nanowall, and polyyne chains, before they are completely removed from the surface of a substrate-bound Ni-nanocluster.We also found that onset of the etching process is different in the cases of the cap and the tube, although the overall etching scenario is similar in both cases. The entire hydrogenation/etching process for both cases is analysed in detail, comparing with available theoretical and experimental evidences. |
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| |
Address |
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Corporate Author |
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Thesis |
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| |
Publisher |
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Place of Publication |
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Editor |
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| |
Language |
|
Wos |
000401120800053 |
Publication Date |
2017-03-26 |
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| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0008-6223 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
6.337 |
Times cited |
2 |
Open Access |
OpenAccess |
|
| |
Notes |
U. K. gratefully acknowledges financial support from the Research Foundation – Flanders (FWO), Belgium (Grant No. 12M1315N). The work was carried out in part using the Turing HPC infrastructure of the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Centre VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the Universiteit Antwerpen. The authors also thank Prof. A. C. T. van Duin for sharing the ReaxFF code. |
Approved |
Most recent IF: 6.337 |
|
| |
Call Number |
PLASMANT @ plasmant @ c:irua:141915 |
Serial |
4531 |
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| Permanent link to this record |
| |
|
| |
|
Author |
Khalilov, U.; Bogaerts, A.; Neyts, E.C. |
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| |
Title |
Toward the Understanding of Selective Si Nano-Oxidation by Atomic Scale Simulations |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Accounts of chemical research |
Abbreviated Journal |
Accounts Chem Res |
|
| |
Volume |
50 |
Issue |
50 |
Pages |
796-804 |
|
| |
Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
|
| |
Abstract |
The continuous miniaturization of nanodevices, such as transistors, solar cells, and optical fibers, requires the controlled synthesis of (ultra)thin gate oxides (<10 nm), including Si gate-oxide (SiO2) with high quality at the atomic scale. Traditional thermal growth of SiO2 on planar Si surfaces, however, does not allow one to obtain such ultrathin oxide due to either the high oxygen diffusivity at high temperature or the very low sticking ability of incident oxygen at low temperature. Two recent techniques, both operative at low (room) temperature, have been put forward to overcome these obstacles: (i) hyperthermal oxidation of planar Si surfaces and (ii) thermal or plasma-assisted oxidation of nonplanar Si surfaces, including Si nanowires (SiNWs). These nanooxidation processes are, however, often difficult to study experimentally, due to the key intermediate processes taking place on the nanosecond time scale.
In this Account, these Si nano-oxidation techniques are discussed from a computational point of view and compared to both hyperthermal and thermal oxidation experiments, as well as to well-known models of thermal oxidation, including the Deal−Grove, Cabrera−Mott, and Kao models and several alternative mechanisms. In our studies, we use reactive molecular dynamics (MD) and hybrid MD/Monte Carlo simulation techniques, applying the Reax force field. The incident energy of oxygen species is chosen in the range of 1−5 eV in hyperthermal oxidation of planar Si surfaces in order to prevent energy-induced damage. It turns out that hyperthermal growth allows for two growth modes, where the ultrathin oxide thickness depends on either (1) only the kinetic energy of the incident oxygen species at a growth temperature below Ttrans = 600 K, or (2) both the incident energy and the growth temperature at a growth temperature above Ttrans. These modes are specific to such ultrathin oxides, and are not observed in traditional thermal oxidation, nor theoretically considered by already existing models. In the case of thermal or plasma-assisted oxidation of small Si nanowires, on the other hand, the thickness of the ultrathin oxide is a function of the growth temperature and the nanowire diameter. Below Ttrans, which varies with the nanowire diameter, partially oxidized SiNW are formed, whereas complete oxidation to a SiO2 nanowire occurs only above Ttrans. In both nano-oxidation processes at lower temperature (T < Ttrans), final sandwich c-Si|SiOx|a-SiO2 structures are obtained due to a competition between overcoming the energy barrier to penetrate into Si subsurface layers and the compressive stress (∼2−3 GPa) at the Si crystal/oxide interface. The overall atomic-simulation results strongly indicate that the thickness of the intermediate SiOx (x < 2) region is very limited (∼0.5 nm) and constant irrespective of oxidation parameters. Thus, control over the ultrathin SiO2 thickness with good quality is indeed possible by accurately tuning the oxidant energy, oxidation temperature and surface curvature.
In general, we discuss and put in perspective these two oxidation mechanisms for obtaining controllable ultrathin gate-oxide films, offering a new route toward the fabrication of nanodevices via selective nano-oxidation. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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| |
Language |
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Wos |
000399859800016 |
Publication Date |
2017-04-18 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0001-4842 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
20.268 |
Times cited |
5 |
Open Access |
OpenAccess |
|
| |
Notes |
Fonds Wetenschappelijk Onderzoek, 12M1315N ; |
Approved |
Most recent IF: 20.268 |
|
| |
Call Number |
PLASMANT @ plasmant @ c:irua:142638 |
Serial |
4561 |
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| Permanent link to this record |
| |
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| |
|
Author |
Khalilov, U.; Bogaerts, A.; Xu, B.; Kato, T.; Kaneko, T.; Neyts, E.C. |
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| |
Title |
How the alignment of adsorbed ortho H pairs determines the onset of selective carbon nanotube etching |
Type |
A1 Journal article |
| |
Year |
2017 |
Publication |
Nanoscale |
Abbreviated Journal |
Nanoscale |
|
| |
Volume |
9 |
Issue |
9 |
Pages |
1653-1661 |
|
| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
|
| |
Abstract |
Unlocking the enormous technological potential of carbon nanotubes strongly depends on our ability to specifically produce metallic or semiconducting tubes. While selective etching of both has already been demonstrated, the underlying reasons, however, remain elusive as yet. We here present computational and experimental evidence on the operative mechanisms at the atomic scale. We demonstrate that during the adsorption of H atoms and their coalescence, the adsorbed ortho hydrogen pairs on single-walled carbon nanotubes induce higher shear stresses than axial stresses, leading to the elongation of HC–CH bonds as a function of their alignment with the tube chirality vector, which we denote as the γ-angle. As a result, the C–C cleavage occurs more rapidly in nanotubes containing ortho H-pairs with a small γ-angle. This phenomenon can explain the selective etching of small-diameter semiconductor nanotubes with a similar curvature. Both theoretical and experimental results strongly indicate the important role of the γ-angle in the selective etching mechanisms of carbon nanotubes, in addition to the nanotube curvature and metallicity effects and lead us to clearly understand the onset of selective synthesis/removal of CNT-based materials. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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| |
Language |
|
Wos |
000395422800036 |
Publication Date |
2016-12-19 |
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| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2040-3364 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
7.367 |
Times cited |
6 |
Open Access |
OpenAccess |
|
| |
Notes |
U. K. gratefully acknowledges financial support from the Fund of Scientific Research Flanders (FWO), Belgium (Grant No. 12M1315N). This work was also supported in part by Grant-in- Aid for Young Scientists A (Grant No. 25706028), Grant-in-Aid for Scientific Research on Innovative Areas (Grant No. 26107502) from JSPS KAKENHI. This work was carried out in part using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen (UA), a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the UA. The authors also thank Prof. A. C. T. van Duin for sharing the ReaxFF code and J. Razzokov for his assistance to perform the DFT calculations. |
Approved |
Most recent IF: 7.367 |
|
| |
Call Number |
PLASMANT @ plasmant @ c:irua:140091 |
Serial |
4417 |
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| Permanent link to this record |
| |
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| |
|
Author |
Khalilov, U.; Neyts, E.C. |
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| |
Title |
Mechanisms of selective nanocarbon synthesis inside carbon nanotubes |
Type |
A1 Journal article |
| |
Year |
2021 |
Publication |
Carbon |
Abbreviated Journal |
Carbon |
|
| |
Volume |
171 |
Issue |
|
Pages |
72-78 |
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| |
Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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| |
Abstract |
The possibility of confinement effects inside a carbon nanotube provides new application opportunities, e.g., growth of novel carbon nanostructures. However, the understanding the precise role of catalystfeedstock in the nanostructure synthesis is still elusive. In our simulation-based study, we investigate the Ni-catalyzed growth mechanism of encapsulated carbon nanostructures, viz. double-wall carbon nanotube and graphene nanoribbon, from carbon and hydrocarbon growth precursors, respectively. Specifically, we find that the tube and ribbon growth is determined by a catalyst-vs-feedstock competition effect. We compare our results, i.e., growth mechanism and structure morphology with all available theoretical and experimental data. Our calculations show that all encapsulated nanostructures contain metal (catalyst) atoms and such structures are less stable than their pure counterparts. Therefore, we study the purification mechanism of these structures. In general, this study opens a possible route to the controllable synthesis of tubular and planar carbon nanostructures for today’s nanotechnology. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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| |
Language |
|
Wos |
000598371500009 |
Publication Date |
2020-09-02 |
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| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0008-6223 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
|
| |
Impact Factor |
6.337 |
Times cited |
|
Open Access |
OpenAccess |
|
| |
Notes |
Fund of Scientific Research Flanders, 12M1318N ; Universiteit Antwerpen; Flemish Supercomputer Centre; Hercules Foundation; Flemish Government; The authors gratefully acknowledge the financial support from the Fund of Scientific Research Flanders (FWO), Belgium, Grant number 12M1318N. The work was carried out in part using the Turing HPC infrastructure of the CalcUA core facility of the Universiteit Antwerpen (UA), a division of the Flemish Supercomputer Centre (VSC), funded by the Hercules Foundation, the Flemish Government (department EWI) and the UA, Belgium. |
Approved |
Most recent IF: 6.337 |
|
| |
Call Number |
PLASMANT @ plasmant @c:irua:172459 |
Serial |
6414 |
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| Permanent link to this record |
| |
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| |
|
Author |
Khalilov, U.; Neyts, E.C.; Pourtois, G.; van Duin, A.C.T. |
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| |
Title |
Can we control the thickness of ultrathin silica layers by hyperthermal silicon oxidation at room temperature? |
Type |
A1 Journal article |
| |
Year |
2011 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
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| |
Volume |
115 |
Issue |
50 |
Pages |
24839-24848 |
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| |
Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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| |
Abstract |
Using reactive molecular dynamics simulations by means of the ReaxFF potential, we studied the growth mechanism of ultrathin silica (SiO2) layers during hyperthermal oxidation at room temperature. Oxidation of Si(100){2 × 1} surfaces by both atomic and molecular oxygen was investigated in the energy range 15 eV. The oxidation mechanism, which differs from thermal oxidation, is discussed. In the case of oxidation by molecular O2, silica is quickly formed and the thickness of the formed layers remains limited compared to oxidation by atomic oxygen. The Si/SiO2 interfaces are analyzed in terms of partial charges and angle distributions. The obtained structures of the ultrathin SiO2 films are amorphous, including some intrinsic defects. This study is important for the fabrication of silica-based devices in the micro- and nanoelectronics industry, and more specifically for the fabrication of metal oxide semiconductor devices. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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| |
Language |
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Wos |
000297947700050 |
Publication Date |
2011-11-16 |
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Series Editor |
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Series Title |
|
Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
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| |
ISSN |
1932-7447;1932-7455; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
4.536 |
Times cited |
36 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 4.536; 2011 IF: 4.805 |
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| |
Call Number |
UA @ lucian @ c:irua:94303 |
Serial |
273 |
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| Permanent link to this record |
| |
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| |
|
Author |
Khalilov, U.; Pourtois, G.; Bogaerts, A.; van Duin, A.C.T.; Neyts, E.C. |
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| |
Title |
Reactive molecular dynamics simulations on SiO2-coated ultra-small Si-nanowires |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
Nanoscale |
Abbreviated Journal |
Nanoscale |
|
| |
Volume |
5 |
Issue |
2 |
Pages |
719-725 |
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| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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| |
Abstract |
The application of coreshell SiSiO2 nanowires as nanoelectronic devices strongly depends on their structure, which is difficult to tune precisely. In this work, we investigate the formation of the coreshell nanowires at the atomic scale, by reactive molecular dynamics simulations. The occurrence of two temperature-dependent oxidation mechanisms of ultra-small diameter Si-NWs is demonstrated. We found that control over the Si-core radius and the SiOx (x ≤ 2) oxide shell is possible by tuning the growth temperature and the initial Si-NW diameter. Two different structures were obtained, i.e., ultrathin SiO2 silica nanowires at high temperature and Si core|ultrathin SiO2 silica nanowires at low temperature. The transition temperature is found to linearly decrease with the nanowire curvature. Finally, the interfacial stress is found to be responsible for self-limiting oxidation, depending on both the initial Si-NW radius and the oxide growth temperature. These novel insights allow us to gain control over the exact morphology and structure of the wires, as is needed for their application in nanoelectronics. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
Cambridge |
Editor |
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| |
Language |
|
Wos |
000313426200036 |
Publication Date |
2012-11-16 |
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| |
Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2040-3364;2040-3372; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
7.367 |
Times cited |
17 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 7.367; 2013 IF: 6.739 |
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| |
Call Number |
UA @ lucian @ c:irua:102584 |
Serial |
2824 |
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| Permanent link to this record |
| |
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| |
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Author |
Khalilov, U.; Pourtois, G.; Huygh, S.; van Duin, A.C.T.; Neyts, E.C.; Bogaerts, A. |
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| |
Title |
New mechanism for oxidation of native silicon oxide |
Type |
A1 Journal article |
| |
Year |
2013 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
|
| |
Volume |
117 |
Issue |
19 |
Pages |
9819-9825 |
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| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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| |
Abstract |
Continued miniaturization of metal-oxide-semiconductor field-effect transistors (MOSFETs) requires an ever-decreasing thickness of the gate oxide. The structure of ultrathin silicon oxide films, however, critically depends on the oxidation mechanism. Using reactive atomistic simulations, we here demonstrate how the oxidation mechanism in hyperthermal oxidation of such structures may be controlled by the oxidation temperature and the oxidant energy. Specifically, we study the interaction of hyperthermal oxygen with energies of 15 eV with thin SiOx (x ≤ 2) films with a native oxide thickness of about 10 Å. We analyze the oxygen penetration depth probability and compare with results of the hyperthermal oxidation of a bare Si(100){2 × 1} (c-Si) surface. The temperature-dependent oxidation mechanisms are discussed in detail. Our results demonstrate that, at low (i.e., room) temperature, the penetrated oxygen mostly resides in the oxide region rather than at the SiOx|c-Si interface. However, at higher temperatures, starting at around 700 K, oxygen atoms are found to penetrate and to diffuse through the oxide layer followed by reaction at the c-Si boundary. We demonstrate that hyperthermal oxidation resembles thermal oxidation, which can be described by the DealGrove model at high temperatures. Furthermore, defect creation mechanisms that occur during the oxidation process are also analyzed. This study is useful for the fabrication of ultrathin silicon oxide gate oxides for metal-oxide-semiconductor devices as it links parameters that can be straightforwardly controlled in experiment (oxygen temperature, velocity) with the silicon oxide structure. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Washington, D.C. |
Editor |
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| |
Language |
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Wos |
000319649100032 |
Publication Date |
2013-04-23 |
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| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| |
Series Volume |
|
Series Issue |
|
Edition |
|
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| |
ISSN |
1932-7447;1932-7455; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
| |
Impact Factor |
4.536 |
Times cited |
24 |
Open Access |
|
|
| |
Notes |
|
Approved |
Most recent IF: 4.536; 2013 IF: 4.835 |
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| |
Call Number |
UA @ lucian @ c:irua:107989 |
Serial |
2321 |
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| Permanent link to this record |
| |
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| |
|
Author |
Khalilov, U.; Pourtois, G.; van Duin, A.C.T.; Neyts, E.C. |
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| |
Title |
Hyperthermal oxidation of Si(100)2x1 surfaces : effect of growth temperature |
Type |
A1 Journal article |
| |
Year |
2012 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
|
| |
Volume |
116 |
Issue |
15 |
Pages |
8649-8656 |
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| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
|
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Abstract |
Using reactive molecular dynamics simulations based on the ReaxFF potential, we studied the growth mechanism of ultrathin silica (SiO2) layers during hyperthermal oxidation as a function of temperature in the range 100-1300 K. Oxidation of Si(100){2 x 1} surfaces by both atomic and molecular oxygen was investigated for hyperthermal impact energies in the range of 1 to 5 eV. Two different growth mechanisms are found, corresponding to a low temperature oxidation and a high temperature one. The transition temperature between these mechanisms is estimated to be about 700 K. Also, the initial step of the Si oxidation process is analyzed in detail. Where possible, we validated our results with experimental and ab initio data, and good agreement was obtained. This study is important for the fabrication of silica-based devices in the micro- and nanoelectronics industry and, more specifically, for the fabrication of metal oxide semiconductor devices. |
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Place of Publication |
Washington, D.C. |
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Wos |
000302924900035 |
Publication Date |
2012-03-26 |
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ISSN |
1932-7447;1932-7455; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.536 |
Times cited |
32 |
Open Access |
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Notes |
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Approved |
Most recent IF: 4.536; 2012 IF: 4.814 |
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Call Number |
UA @ lucian @ c:irua:98259 |
Serial |
1542 |
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Author |
Khalilov, U.; Pourtois, G.; van Duin, A.C.T.; Neyts, E.C. |
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Title |
On the c-Si\mid a-SiO2 interface in hyperthermal Si oxidation at room temperature |
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A1 Journal article |
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Year |
2012 |
Publication |
The journal of physical chemistry: C : nanomaterials and interfaces |
Abbreviated Journal |
J Phys Chem C |
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Volume |
116 |
Issue |
41 |
Pages |
21856-21863 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
The exact structure and properties of the Si vertical bar SiO2 interface are very important in microelectronics and photovoltaic devices such as metal-oxide-semiconductor field-effect transistors (MOSFETs) and solar cells. Whereas Si vertical bar SiO2 structures are traditionally produced by thermal oxidation, hyperthermal oxidation shows a number of promising advantages. However, the Si vertical bar SiO2 interface induced in hyperthermal Si oxidation has not been properly investigated yet. Therefore, in this work, the interface morphology and interfacial stresses during hyperthermal oxidation at room temperature are studied using reactive molecular dynamics simulations based on the ReaxFF potential. Interface thickness and roughness, as well as the bond length and bond angle distributions in the interface are discussed and compared with other models developed for the interfaces induced by traditional thermal oxidation. The formation of a compressive stress is observed. This compressive stress, which at the interface amounts about 2 GPa, significantly slows down the inward silica growth. This value is close to the experimental value in the Si vertical bar SiO2 interface obtained in traditional thermal oxidation. |
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Place of Publication |
Washington, D.C. |
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Wos |
000309902100026 |
Publication Date |
2012-09-26 |
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Edition |
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ISSN |
1932-7447;1932-7455; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.536 |
Times cited |
27 |
Open Access |
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Notes |
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Approved |
Most recent IF: 4.536; 2012 IF: 4.814 |
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Call Number |
UA @ lucian @ c:irua:102167 |
Serial |
2458 |
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Author |
Khalilov, U.; Pourtois, G.; van Duin, A.C.T.; Neyts, E.C. |
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Title |
Self-limiting oxidation in small-diameter Si nanowires |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
24 |
Issue |
11 |
Pages |
2141-2147 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
Recently, core shell silicon nanowires (Si-NWs) have been envisaged to be used for field-effect transistors and photovoltaic applications. In spite of the constant downsizing of such devices, the formation of ultrasmall diameter core shell Si-NWs currently remains entirely unexplored. We report here on the modeling of the formation of such core shell Si-NWs using a dry thermal oxidation of 2 nm diameter (100) Si nanowires at 300 and 1273 K, by means of reactive molecular dynamics simulations using the ReaxFF potential. Two different oxidation mechanisms are discussed, namely a self-limiting process that occurs at low temperature (300 K), resulting in a Si core I ultrathin SiO2 silica shell nanowire, and a complete oxidation process that takes place at a higher temperature (1273 K), resulting in the formation of an ultrathin SiO2 silica nanowire. The oxidation kinetics of both cases and the resulting structures are analyzed in detail. Our results demonstrate that precise control over the Si-core radius of such NWs and the SiOx (x <= 2.0) oxide shell is possible by controlling the growth temperature used during the oxidation process. |
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Place of Publication |
Washington, D.C. |
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Wos |
000305092600021 |
Publication Date |
2012-05-18 |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
45 |
Open Access |
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Notes |
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Approved |
Most recent IF: 9.466; 2012 IF: 8.238 |
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Call Number |
UA @ lucian @ c:irua:99079 |
Serial |
2976 |
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