Home << 1 2 3 4 >>
List View
 | 
Citations
 | 
Details
   web
Records
Author Clima, S.; Garbin, D.; Devulder, W.; Keukelier, J.; Opsomer, K.; Goux, L.; Kar, G.S.; Pourtois, G.
Title Material relaxation in chalcogenide OTS SELECTOR materials Type A1 Journal article
Year 2019 Publication Microelectronic engineering Abbreviated Journal Microelectron Eng
Volume 215 Issue 215 Pages 110996
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Nature of the mobility-gap states in amorphous Ge-rich Ge50Se50 was found to be related to homopolar Ge bonds in the chains/clusters of Ge atoms. Threshold switching material suffers Ge-Ge bond concentration drift during material ageing, which can explain the observed reliability of the aGe(50)Se(50) selector devices. Strong Ge-N bonds were introduced to alleviate the observed instability.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000480665600008 Publication Date 2019-05-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0167-9317 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 1.806 Times cited 1 Open Access
Notes Approved Most recent IF: 1.806
Call Number UA @ admin @ c:irua:161905 Serial 6308
Permanent link to this record
 
 
Author Phung, Q.M.; Vancoillie, S.; Delabie, A.; Pourtois, G.; Pierloot, K.
Title Ruthenocene and cyclopentadienyl pyrrolyl ruthenium as precursors for ruthenium atomic layer deposition : a comparative study of dissociation enthalpies Type A1 Journal article
Year 2012 Publication Theoretical chemistry accounts : theory, computation, and modeling Abbreviated Journal Theor Chem Acc
Volume 131 Issue 7 Pages 1238
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract RuCp2 (ruthenocene) and RuCpPy (cyclopentadienyl pyrrolyl ruthenium) complexes are used in ruthenium (Ru) atomic layer deposition (ALD) but exhibit a markedly different reactivity with respect to the substrate and co-reactant. In search of an explanation, we report here the results of a comparative study of the heterolytic and homolytic dissociation enthalpy of these two ruthenium complexes, making use of either density functional theory (DFT) or multiconfigurational perturbation theory (CASPT2). While both methods predict distinctly different absolute dissociation enthalpies, they agree on the relative values between both molecules. A reduced heterolytic dissociation enthalpy is obtained for RuCpPy compared to RuCp2, although the difference obtained from CASPT2 (19.9 kcal/mol) is slightly larger than the one obtained with any of the DFT functionals (around 17 kcal/mol). Both methods also agree on the more pronounced stability of the Cp- ligand in RuCpPy than in RuCp2 (by around 9 kcal/mol with DFT and by 6 kcal/mol with CASPT2).
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000307274300003 Publication Date 2012-07-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1432-881X;1432-2234; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 1.89 Times cited 5 Open Access
Notes Approved Most recent IF: 1.89; 2012 IF: 2.233
Call Number UA @ lucian @ c:irua:101139 Serial 2935
Permanent link to this record
 
 
Author Schoeters, B.; Leenaerts, O.; Pourtois, G.; Partoens, B.
Title Ab-initio study of the segregation and electronic properties of neutral and charged B and P dopants in Si and Si/SiO2 nanowires Type A1 Journal article
Year 2015 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 118 Issue 118 Pages 104306
Keywords A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract We perform first-principles calculations to investigate the preferred positions of B and P dopants, both neutral and in their preferred charge state, in Si and Si/SiO2 core-shell nanowires (NWs). In order to understand the observed trends in the formation energy, we isolate the different effects that determine these formation energies. By making the distinction between the unrelaxed and the relaxed formation energy, we separate the impact of the relaxation from that of the chemical environment. The unrelaxed formation energies are determined by three effects: (i) the effect of strain caused by size mismatch between the dopant and the host atoms, (ii) the local position of the band edges, and (iii) a screening effect. In the case of the SiNW (Si/SiO2 NW), these effects result in an increase of the formation energy away from the center (interface). The effect of relaxation depends on the relative size mismatch between the dopant and host atoms. A large size mismatch causes substantial relaxation that reduces the formation energy considerably, with the relaxation being more pronounced towards the edge of the wires. These effects explain the surface segregation of the B dopants in a SiNW, since the atomic relaxation induces a continuous drop of the formation energy towards the edge. However, for the P dopants, the formation energy starts to rise when moving from the center but drops to a minimum just next to the surface, indicating a different type of behavior. It also explains that the preferential location for B dopants in Si/SiO2 core-shell NWs is inside the oxide shell just next to the interface, whereas the P dopants prefer the positions next to the interface inside the Si core, which is in agreement with recent experiments. These preferred locations have an important impact on the electronic properties of these core-shell NWs. Our simulations indicate the possibility of hole gas formation when B segregates into the oxide shell.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000361636900031 Publication Date 2015-09-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 2.068 Times cited 3 Open Access
Notes This work was carried out using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish government and the Universiteit Antwerpen. Approved Most recent IF: 2.068; 2015 IF: 2.183
Call Number c:irua:128729 Serial 4056
Permanent link to this record
 
 
Author Clima, S.; Chen, Y.Y.; Chen, C.Y.; Goux, L.; Govoreanu, B.; Degraeve, R.; Fantini, A.; Jurczak, M.; Pourtois, G.
Title First-principles thermodynamics and defect kinetics guidelines for engineering a tailored RRAM device Type A1 Journal article
Year 2016 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 119 Issue 119 Pages 225107
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Resistive Random Access Memories are among the most promising candidates for the next generation of non-volatile memory. Transition metal oxides such as HfOx and TaOx attracted a lot of attention due to their CMOS compatibility. Furthermore, these materials do not require the inclusion of extrinsic conducting defects since their operation is based on intrinsic ones (oxygen vacancies). Using Density Functional Theory, we evaluated the thermodynamics of the defects formation and the kinetics of diffusion of the conducting species active in transition metal oxide RRAM materials. The gained insights based on the thermodynamics in the Top Electrode, Insulating Matrix and Bottom Electrode and at the interfaces are used to design a proper defect reservoir, which is needed for a low-energy reliable switching device. The defect reservoir has also a direct impact on the retention of the Low Resistance State due to the resulting thermodynamic driving forces. The kinetics of the diffusing conducting defects in the Insulating Matrix determine the switching dynamics and resistance retention. The interface at the Bottom Electrode has a significant impact on the low-current operation and long endurance of the memory cell. Our first-principles findings are confirmed by experimental measurements on fabricated RRAM devices. Published by AIP Publishing.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000378925400035 Publication Date 2016-06-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; 1089-7550 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 2.068 Times cited 17 Open Access
Notes Approved Most recent IF: 2.068
Call Number UA @ lucian @ c:irua:134651 Serial 4181
Permanent link to this record
 
 
Author Dutta, S.; Sankaran, K.; Moors, K.; Pourtois, G.; Van Elshocht, S.; Bommels, J.; Vandervorst, W.; Tokei, Z.; Adelmann, C.
Title Thickness dependence of the resistivity of platinum-group metal thin films Type A1 Journal article
Year 2017 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 122 Issue 2 Pages 025107
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract We report on the thin film resistivity of several platinum-group metals (Ru, Pd, Ir, and Pt). Platinum-group thin films show comparable or lower resistivities than Cu for film thicknesses below about 5 nm due to a weaker thickness dependence of the resistivity. Based on experimentally determined mean linear distances between grain boundaries as well as ab initio calculations of the electron mean free path, the data for Ru, Ir, and Cu were modeled within the semiclassical Mayadas-Shatzkes model [Phys. Rev. B 1, 1382 (1970)] to assess the combined contributions of surface and grain boundary scattering to the resistivity. For Ru, the modeling results indicated that surface scattering was strongly dependent on the surrounding material with nearly specular scattering at interfaces with SiO2 or air but with diffuse scattering at interfaces with TaN. The dependence of the thin film resistivity on the mean free path is also discussed within the Mayadas-Shatzkes model in consideration of the experimental findings. Published by AIP Publishing.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000405663800038 Publication Date 2017-07-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; 1089-7550 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 2.068 Times cited 42 Open Access Not_Open_Access
Notes Approved Most recent IF: 2.068
Call Number UA @ lucian @ c:irua:145213 Serial 4729
Permanent link to this record
 
 
Author de de Meux, A.J.; Pourtois, G.; Genoe, J.; Heremans, P.
Title Effects of hole self-trapping by polarons on transport and negative bias illumination stress in amorphous-IGZO Type A1 Journal article
Year 2018 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 123 Issue 16 Pages 161513
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The effects of hole injection in amorphous indium-gallium-zinc-oxide (a-IGZO) are analyzed by means of first-principles calculations. The injection of holes in the valence band tail states leads to their capture as a polaron, with high self-trapping energies (from 0.44 to 1.15 eV). Once formed, they mediate the formation of peroxides and remain localized close to the hole injection source due to the presence of a large diffusion energy barrier (of at least 0.6 eV). Their diffusion mechanism can be mediated by the presence of hydrogen. The capture of these holes is correlated with the low off-current observed for a-IGZO transistors, as well as with the difficulty to obtain a p-type conductivity. The results further support the formation of peroxides as being the root cause of Negative Bias Illumination Stress (NBIS). The strong self-trapping substantially reduces the injection of holes from the contact and limits the creation of peroxides from a direct hole injection. In the presence of light, the concentration of holes substantially rises and mediates the creation of peroxides, responsible for NBIS. Published by AIP Publishing.
Address
Corporate Author Thesis
Publisher Amer inst physics Place of Publication Melville Editor
Language Wos 000431147200043 Publication Date 2017-10-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; 1089-7550 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 2.068 Times cited 4 Open Access OpenAccess
Notes Approved Most recent IF: 2.068
Call Number UA @ lucian @ c:irua:151570 Serial 5021
Permanent link to this record
 
 
Author Vohra, A.; Khanam, A.; Slotte, J.; Makkonen, I.; Pourtois, G.; Loo, R.; Vandervorst, W.
Title Evolution of phosphorus-vacancy clusters in epitaxial germanium Type A1 Journal article
Year 2019 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 125 Issue 2 Pages 025701
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The E centers (dopant-vacancy pairs) play a significant role in dopant deactivation in semiconductors. In order to gain insight into dopant-defect interactions during epitaxial growth of in situ phosphorus doped Ge, positron annihilation spectroscopy, which is sensitive to open-volume defects, was performed on Ge layers grown by chemical vapor deposition with different concentrations of phosphorus (similar to 1 x 10(18)-1 x 10(20) cm(-3)). Experimental results supported by first-principles calculations based on the two component density-functional theory gave evidence for the existence of mono-vacancies decorated by several phosphorus atoms as the dominant defect type in the epitaxial Ge. The concentration of vacancies increases with the amount of P-doping. The number of P atoms around the vacancy also increases, depending on the P concentration. The evolution of P-n-V clusters in Ge contributes significantly to the dopant deactivation. Published under license by AIP Publishing.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000455922100057 Publication Date 2019-01-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; 1089-7550 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 2.068 Times cited 5 Open Access Not_Open_Access
Notes Approved Most recent IF: 2.068
Call Number UA @ admin @ c:irua:156722 Serial 5274
Permanent link to this record
 
 
Author Vohra, A.; Khanam, A.; Slotte, J.; Makkonen, I.; Pourtois, G.; Porret, C.; Loo, R.; Vandervorst, W.
Title Heavily phosphorus doped germanium : strong interaction of phosphorus with vacancies and impact of tin alloying on doping activation Type A1 Journal article
Year 2019 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 125 Issue 22 Pages 225703
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract We examined the vacancy trapping proficiency of Sn and P atoms in germanium using positron annihilation spectroscopy measurements, sensitive to the open-volume defects. Epitaxial Ge1 xSnx films were grown by chemical vapor deposition with different P concentrations in the 3: 0 1019-1: 5 1020 cm 3 range. We corroborate our findings with first principles simulations. Codoping of Ge with a Sn concentration of up to 9% is not an efficient method to suppress the free vacancy concentration and the formation of larger phosphorus-vacancy complexes. Experimental results confirm an increase in the number of P atoms around the monovacancy with P-doping, leading to dopant deactivation in epitaxial germanium-tin layers with similar Sn content. Vice versa, no impact on the improvement of maximum achieved P activation in Ge with increasing Sn-doping has been observed. Theoretical calculations also confirm that Pn-V (vacancy) complexes are energetically more stable than the corresponding SnmPn-V and Snm-V defect structures with the same number of alien atoms (Sn or P) around the monovacancy. he strong attraction of vacancies to the phosphorus atoms remains the dominant dopant deactivation mechanism in Ge as well as in Ge1 xSnx. Published under license by AIP Publishing.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000471698600044 Publication Date 2019-06-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; 1089-7550 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 2.068 Times cited 1 Open Access
Notes Approved Most recent IF: 2.068
Call Number UA @ admin @ c:irua:161333 Serial 6300
Permanent link to this record
 
 
Author Vohra, A.; Makkonen, I.; Pourtois, G.; Slotte, J.; Porret, C.; Rosseel, E.; Khanam, A.; Tirrito, M.; Douhard, B.; Loo, R.; Vandervorst, W.
Title Source/drain materials for Ge nMOS devices: phosphorus activation in epitaxial Si, Ge, Ge1-xSnx and SiyGe1-x-ySnx Type A1 Journal article
Year 2020 Publication Ecs Journal Of Solid State Science And Technology Abbreviated Journal Ecs J Solid State Sc
Volume 9 Issue 4 Pages 044010-44012
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract This paper benchmarks various epitaxial growth schemes based on n-type group-IV materials as viable source/drain candidates for Ge nMOS devices. Si:P grown at low temperature on Ge, gives an active carrier concentration as high as 3.5 x 10(20) cm(-3) and a contact resistivity down to 7.5 x 10(-9) Omega.cm(2). However, Si:P growth is highly defective due to large lattice mismatch between Si and Ge. Within the material stacks assessed, one option for Ge nMOS source/drain stressors would be to stack Si:P, deposited at contact level, on top of a selectively grown n-SiyGe1-x-ySnx at source/drain level, in line with the concept of Si passivation of n-Ge surfaces to achieve low contact resistivities as reported in literature (Martens et al. 2011 Appl. Phys. Lett., 98, 013 504). The saturation in active carrier concentration with increasing P (or As)-doping is the major bottleneck in achieving low contact resistivities for as-grown Ge or SiyGe1-x-ySnx. We focus on understanding various dopant deactivation mechanisms in P-doped Ge and Ge1-xSnx alloys. First principles simulation results suggest that P deactivation in Ge and Ge1-xSnx can be explained both by P-clustering and donor-vacancy complexes. Positron annihilation spectroscopy analysis, suggests that dopant deactivation in P-doped Ge and Ge1-xSnx is primarily due to the formation of P-n-V and SnmPn-V clusters. (C) 2020 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000531473500002 Publication Date 2020-04-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2162-8769; 2162-8777 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 2.2 Times cited Open Access
Notes ; The imec core CMOS program members, European Commission, the TAKEMI5 ECSEL project, local authorities and the imec pilot line are acknowledged for their support. Air Liquide Advanced Materials is acknowledged for providing advanced precursor gases. A. V. acknowledges his long stay abroad grant and a grant for participation in congress abroad from the Research Foundation-Flanders (Application No. V410518N and K159219N). I. M. acknowledges financial support from Academy of Finland (Project Nos. 285 809, 293 932 and 319 178). CSC-IT Center for Science, Finland is acknowledged for providing the computational resources. ; Approved Most recent IF: 2.2; 2020 IF: 1.787
Call Number UA @ admin @ c:irua:169502 Serial 6607
Permanent link to this record
 
 
Author Scalise, E.; Houssa, M.; Pourtois, G.; Afanas'ev, V.V.; Stesmans, A.
Title First-principles study of strained 2D MoS2 Type A1 Journal article
Year 2014 Publication Physica. E: Low-dimensional systems and nanostructures Abbreviated Journal Physica E
Volume 56 Issue Pages 416-421
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The electronic and vibrational properties of 2D honeycomb structures of molybdenum disulfide (MoS2) subjected to strain have been investigated using first-principles calculations based on density functional theory. We have studied the evolution of the electronic properties of bulk and layered MoS2, going down from a few layers up to a mono-layer, and next investigated the effect of bi-axial strain on their electronic structure and vibrational frequencies. Both for tensile and compressive biaxial strains, the shrinking of the energy band-gap of MoS2 with increasing level of applied strain is observed and a transition limit of the system from semiconducting to metallic is predicted to occur for strains in the range of 8-10%. We also found a progressive downshift (upshift) of both the E-2g(1) and A(1g) Raman active modes with increasing level of applied tensile (compressive) strain. Interestingly, significant changes in the curvature of the conduction and valence band near their extrema upon the application of strain are also predicted, with correlated variations of the electron and hole effective masses. These changes present interesting possibilities for engineering the electronic properties of 2D structures of MoS2. (C) 2012 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher North-Holland Place of Publication Amsterdam Editor
Language Wos 000330815800070 Publication Date 2012-08-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1386-9477; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 2.221 Times cited 72 Open Access
Notes Approved Most recent IF: 2.221; 2014 IF: 2.000
Call Number UA @ lucian @ c:irua:115761 Serial 1220
Permanent link to this record
 
 
Author Hardy, A.; Van Elshocht, S.; De Dobbelaere, C.; Hadermann, J.; Pourtois, G.; De Gendt, S.; Afanas'ev, V.V.; Van Bael, M.K.
Title Properties and thermal stability of solution processed ultrathin, high-k bismuth titanate (Bi2Ti2O7) films Type A1 Journal article
Year 2012 Publication Materials research bulletin Abbreviated Journal Mater Res Bull
Volume 47 Issue 3 Pages 511-517
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Ultrathin bismuth titanate films (Bi2Ti2O7, 5-25 nm) are deposited onto SiO2/Si substrates by aqueous chemical solution deposition and their evolution during annealing is studied. The films crystallize into a preferentially oriented, pure pyrochlore phase between 500 and 700 degrees C, depending on the film thickness and the total thermal budget. Crystallization causes a strong increase of surface roughness compared to amorphous films. An increase of the interfacial layer thickness is observed after anneal at 600 degrees C, together with intermixing of bismuth with the substrate as shown by TEM-EDX. The band gap was determined to be similar to 3 eV from photoconductivity measurements and high dielectric constants between 30 and 130 were determined from capacitance voltage measurements, depending on the processing conditions. (C) 2012 Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication New York, N.Y. Editor
Language Wos 000301994100001 Publication Date 2012-01-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0025-5408; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 2.446 Times cited Open Access
Notes Approved Most recent IF: 2.446; 2012 IF: 1.913
Call Number UA @ lucian @ c:irua:97797 Serial 2727
Permanent link to this record
 
 
Author de de Meux, A.J.; Pourtois, G.; Genoe, J.; Heremans, P.
Title Comparison of the electronic structure of amorphous versus crystalline indium gallium zinc oxide semiconductor : structure, tail states and strain effects Type A1 Journal article
Year 2015 Publication Journal of physics: D: applied physics Abbreviated Journal J Phys D Appl Phys
Volume 48 Issue 48 Pages 435104
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract We study the evolution of the structural and electronic properties of crystalline indium gallium zinc oxide (IGZO) upon amorphization by first-principles calculation. The bottom of the conduction band (BCB) is found to be constituted of a pseudo-band of molecular orbitals that resonate at the same energy on different atomic sites. They display a bonding character between the s orbitals of the metal sites and an anti-bonding character arising from the interaction between the oxygen and metal s orbitals. The energy level of the BCB shifts upon breaking of the crystal symmetry during the amorphization process, which may be attributed to the reduction of the coordination of the cationic centers. The top of the valence band (TVB) is constructed from anti-bonding oxygen p orbitals. In the amorphous state, they have random orientation, in contrast to the crystalline state. This results in the appearance of localized tail states in the forbidden gap above the TVB. Zinc is found to play a predominant role in the generation of these tail states, while gallium hinders their formation. Last, we study the dependence of the fundamental gap and effective mass of IGZO on mechanical strain. The variation of the gap under strain arises from the enhancement of the anti-bonding interaction in the BCB due to the modification of the length of the oxygen-metal bonds and/or to a variation of the cation coordination. This effect is less pronounced for the amorphous material compared to the crystalline material, making amorphous IGZO a semiconductor of choice for flexible electronics. Finally, the effective mass is found to increase upon strain, in contrast to regular materials. This counterintuitive variation is due to the reduction of the electrostatic shielding of the cationic centers by oxygen, leading to an increase of the overlaps between the metal orbitals at the origin of the delocalization of the BCB. For the range of strain typically met in flexible electronics, the induced variation in the effective mass is found to be negligible (less than 1%).
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000365876300012 Publication Date 2015-09-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3727 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 2.588 Times cited 23 Open Access
Notes Approved Most recent IF: 2.588; 2015 IF: 2.721
Call Number UA @ lucian @ c:irua:130277 Serial 4153
Permanent link to this record
 
 
Author de de Meux, A.J.; Pourtois, G.; Genoe, J.; Heremans, P.
Title Origin of the apparent delocalization of the conduction band in a high-mobility amorphous semiconductor Type A1 Journal article
Year 2017 Publication Journal of physics : condensed matter Abbreviated Journal J Phys-Condens Mat
Volume 29 Issue 25 Pages 255702
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this paper, we show that the apparent delocalization of the conduction band reported from first-principles simulations for the high-mobility amorphous oxide semiconductor InGaZnO4 (a-IGZO) is an artifact induced by the periodic conditions imposed to the model. Given a sufficiently large unit-cell dimension (over 40 angstrom), the conduction band becomes localized. Such a model size is up to four times the size of commonly used models for the study of a-IGZO. This finding challenges the analyses done so far on the nature of the defects and on the interpretation of numerous electrical measurements. In particular, we re-interpret the meaning of the computed effective mass reported so far in literature. Our finding also applies to materials such as SiZnSnO, ZnSnO, InZnSnO, In2O3 or InAlZnO4 whose models have been reported to display a fully delocalized conduction band in the amorphous phase.
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000402434900002 Publication Date 2017-02-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0953-8984 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 2.649 Times cited 5 Open Access Not_Open_Access
Notes Approved Most recent IF: 2.649
Call Number UA @ lucian @ c:irua:144183 Serial 4676
Permanent link to this record
 
 
Author Clima, S.; Garbin, D.; Opsomer, K.; Avasarala, N.S.; Devulder, W.; Shlyakhov, I.; Keukelier, J.; Donadio, G.L.; Witters, T.; Kundu, S.; Govoreanu, B.; Goux, L.; Detavernier, C.; Afanas'ev, V.; Kar, G.S.; Pourtois, G.
Title Ovonic threshold-switching GexSey chalcogenide materials : stoichiometry, trap nature, and material relaxation from first principles Type A1 Journal article
Year 2020 Publication Physica Status Solidi-Rapid Research Letters Abbreviated Journal Phys Status Solidi-R
Volume Issue Pages 1900672
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Density functional theory simulations are used to identify the structural factors that define the material properties of ovonic threshold switches (OTS). They show that the nature of mobility-gap trap states in amorphous Ge-rich Ge50Se50 is related to Ge-Ge bonds, whereas in Se-rich Ge30Se70 the Ge valence-alternating-pairs and Se lone-pairs dominate. To obtain a faithful description of the electronic structure and delocalization of states, it is required to combine hybrid exchange-correlation functionals with large unit-cell models. The extent of localization of electronic states depends on the applied external electric field. Hence, OTS materials undergo structural changes during electrical cycling of the device, with a decrease in the population of less exothermic Ge-Ge bonds in favor of more exothermic Ge-Se. This reduces the amount of charge traps, which translates into coordination changes, an increase in mobility-gap, and subsequently changes in the selector-device electrical parameters. The threshold voltage drift process can be explained by natural evolution of the nonpreferred Ge-Ge bonds (or “chains”/clusters thereof) in Ge-rich GexSe1-x. The effect of extrinsic doping is shown for Si and N, which introduce strong covalent bonds into the system, increase both mobility-gap and crystallization temperature, and decrease the leakage current.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000512431100001 Publication Date 2020-01-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1862-6254 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 2.8 Times cited 3 Open Access
Notes ; This work was carried out in the framework of the imec Core CMOS-Emerging Memory Program. Financial support from EU H2020-NMBPTO-IND-2018 project “INTERSECT” (Grant No. 814487) is acknowledged. ; Approved Most recent IF: 2.8; 2020 IF: 3.032
Call Number UA @ admin @ c:irua:166492 Serial 6575
Permanent link to this record
 
 
Author van den Broek, B.; Houssa, M.; Pourtois, G.; Afanas'ev, V.V.; Stesmans, A.
Title Current-voltage characteristics of armchair Sn nanoribbons Type A1 Journal article
Year 2014 Publication Physica status solidi: rapid research letters Abbreviated Journal Phys Status Solidi-R
Volume 8 Issue 11 Pages 931-934
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Two-dimensional group-IV lattices silicene and germanene are known to share many of graphene's remarkable mechanical and electronic properties. Due to the out-of-plane buckling of the former materials, there are more means of electronic funtionalization, e.g. by applying uniaxial strain or an out-of-plane electric field. We consider monolayer hexagonal Sn (stanene) as an ideal candidate to feasibly implement and exploit graphene physics for nanoelectronic applications: with increased out-of-plane buckling and sizable spin-orbit coupling it lends itself to improved Dirac cone engineering. We investigate the ballistic charge transport regime of armchair Sn nanoribbons, classified according to the ribbon width W = {3m – 1, 3m, 3m + 1} with integer m. We study transport through (non-magnetic) armchair ribbons using a combination of density functional theory and non-equilibrium Green's functions. Sn ribbons have earlier current onsets and carry currents 20% larger than C/Si/Ge-nanoribbons as the contact resistance of these ribbons is found to be comparable. ((c) 2014 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)
Address
Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos 000345274300009 Publication Date 2014-09-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1862-6254; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 3.032 Times cited 9 Open Access
Notes Approved Most recent IF: 3.032; 2014 IF: 2.142
Call Number UA @ lucian @ c:irua:122148 Serial 594
Permanent link to this record
 
 
Author Clima, S.; Sankaran, K.; Chen, Y.Y.; Fantini, A.; Celano, U.; Belmonte, A.; Zhang, L.; Goux, L.; Govoreanu, B.; Degraeve, R.; Wouters, D.J.; Jurczak, M.; Vandervorst, W.; Gendt, S.D.; Pourtois, G.;
Title RRAMs based on anionic and cationic switching : a short overview Type A1 Journal article
Year 2014 Publication Physica status solidi: rapid research letters Abbreviated Journal Phys Status Solidi-R
Volume 8 Issue 6 Pages 501-511
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Resistive random access memories are emerging as a new type of memory that has the potential to combine both the speed of volatile and the retention of nonvolatile memories. It operates based on the formation/dissolution of a low-resistivity filament being constituted of either metallic ions or atomic vacancies within an insulating matrix. At present, the mechanisms and the parameters controlling the performances of the device remain unclear. In that respect, first-principles simulations provide useful insights on the atomistic mechanisms, the thermodynamic and kinetics factors that modulate the material conductivity, providing guidance into the engineering of the operation of the device. In this paper, we review the current state-of-the-art knowledge on the atomistic switching mechanisms driving the operation of copper-based conductive bridge RRAM and HfOx valence change RRAM. [GRAPHICS] Conceptual illustration of the RRAM device with the filament formation and disruption during its operation. AE/IM/CE are the active electrode/insulating matrix/counterelectrode. The blue circles represent the conducting defects. (C) 2014 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim
Address
Corporate Author Thesis
Publisher Place of Publication Berlin Editor
Language Wos 000338021200004 Publication Date 2014-04-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1862-6254; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 3.032 Times cited 28 Open Access
Notes Approved Most recent IF: 3.032; 2014 IF: 2.142
Call Number UA @ lucian @ c:irua:118679 Serial 2933
Permanent link to this record
 
 
Author Clima, S.; Kaczer, B.; Govoreanu, B.; Popovici, M.; Swerts, J.; Verhulst, A.S.; Jurczak, M.; De Gendt, S.; Pourtois, G.
Title Determination of ultimate leakage through rutile TiO2 and tetragonal ZrO2 from ab initio complex band calculations Type A1 Journal article
Year 2013 Publication IEEE electron device letters Abbreviated Journal Ieee Electr Device L
Volume 34 Issue 3 Pages 402-404
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract First-principle complex band structures have been computed for rutile TiO2 and tetragonal ZrO2 insulating materials that are of current technological relevance to dynamic random accessmemorymetal-insulator-metal (MIM) capacitors. From the magnitude of the complex wave vectors in different orientations, the most penetrating orientations have been identified. Tunneling effective masses m(tunnel) have been extracted, are shown to be a crucial parameter for the intrinsic leakage, and are identified to be an important parameter in further scaling of MIM capacitors.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000315723000024 Publication Date 2013-01-31
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0741-3106;1558-0563; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 3.048 Times cited 3 Open Access
Notes Approved Most recent IF: 3.048; 2013 IF: 3.023
Call Number UA @ lucian @ c:irua:108295 Serial 680
Permanent link to this record
 
 
Author Clima, S.; Chen, Y.Y.; Fantini, A.; Goux, L.; Degraeve, R.; Govoreanu, B.; Pourtois, G.; Jurczak, M.
Title Intrinsic tailing of resistive states distributions in amorphous <tex>HfOx </tex> and TaOx based resistive random access memories Type A1 Journal article
Year 2015 Publication IEEE electron device letters Abbreviated Journal Ieee Electr Device L
Volume 36 Issue 36 Pages 769-771
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract We report on the ineffectiveness of programming oxide-based resistive random access memory (OxRAM) at low current with a program and verify algorithm due to intrinsic relaxation of the verified distribution to the natural state distribution obtained by single-pulse programming without verify process. Based on oxygen defect formation thermodynamics and on their diffusion barriers in amorphous HfOx and TaOx, we describe the intrinsic nature of tailing of the verified low resistive state and high resistive state distributions. We introduce different scenarios to explain fast distribution widening phenomenon, which is a fundamental limitation for OxRAM current scaling and device reliability.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000358570300011 Publication Date 2015-06-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0741-3106 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 3.048 Times cited 33 Open Access
Notes Approved Most recent IF: 3.048; 2015 IF: 2.754
Call Number UA @ lucian @ c:irua:134412 Serial 4200
Permanent link to this record
 
 
Author Cornil, D.; Li, H.; Wood, C.; Pourtois, G.; Bredas, J.-L.; Cornil, J.
Title Work-function modification of Au and Ag surfaces upon deposition of self-assembled monolayers : influence of the choice of the theoretical approach and the thiol decomposition scheme Type A1 Journal article
Year 2013 Publication ChemPhysChem : a European journal of chemical physics and physical chemistry Abbreviated Journal Chemphyschem
Volume 14 Issue 13 Pages 2939-2946
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract We have characterized theoretically the work-function modifications of the (111) surfaces of gold and silver upon deposition of self-assembled monolayers based on methanethiol and trifluoromethanethiol. A comparative analysis is made between the experimental results and those obtained from two widely used approaches based on density functional theory. The contributions to the total work-function modifications are estimated on the basis of two decomposition schemes of the thiol molecules that have been proposed in the literature. The contributions are found to differ significantly between the two approaches, as do the corresponding adsorption energies.
Address
Corporate Author Thesis
Publisher Place of Publication Weinheim Editor
Language Wos 000324316000014 Publication Date 2013-07-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1439-4235; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 3.075 Times cited 9 Open Access
Notes Approved Most recent IF: 3.075; 2013 IF: 3.360
Call Number UA @ lucian @ c:irua:112278 Serial 3923
Permanent link to this record
 
 
Author Khanam, A.; Vohra, A.; Slotte, J.; Makkonen, I.; Loo, R.; Pourtois, G.; Vandervorst, W.
Title A demonstration of donor passivation through direct formation of V-As-i complexes in As-doped Ge1-XSnx Type A1 Journal article
Year 2020 Publication Journal Of Applied Physics Abbreviated Journal J Appl Phys
Volume 127 Issue 19 Pages 195703
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Positron annihilation spectroscopy in the Doppler and coincidence Doppler mode was applied on Ge1 xSnx epitaxial layers, grown by chemical vapor deposition with different total As concentrations (1019-1021 cm3), high active As concentrations (1019 cm3), and similar Sn concentrations (5.9%-6.4%). Positron traps are identified as mono-vacancy complexes. Vacancy-As complexes, V-Asi, formed during the growth were studied to deepen the understanding of the electrical passivation of the Ge1 xSnx:As epilayers. Larger monovacancy complexes, V-Asi (i 2), are formed as the As doping increases. The total As concentration shows a significant impact on the saturation of the number of As atoms (i 1/4 4) around the vacancies in the sample epilayers. The presence of V-Asi complexes decreases the dopant activation in the Ge1 xSnx:As epilayers. Furthermore, the presence of Sn failed to hinder the formation of larger V-Asi complexes and thus failed to reduce the donor-deactivation.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000536196000003 Publication Date 2020-05-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; 1089-7550 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 3.2 Times cited Open Access
Notes ; ; Approved Most recent IF: 3.2; 2020 IF: 2.068
Call Number UA @ admin @ c:irua:170252 Serial 6447
Permanent link to this record
 
 
Author van den Broek, B.; Houssa, M.; Scalise, E.; Pourtois, G.; Afanas'ev, V.V.; Stesmans, A.
Title First-principles electronic functionalization of silicene and germanene by adatom chemisorption Type A1 Journal article
Year 2014 Publication Applied surface science Abbreviated Journal Appl Surf Sci
Volume 291 Issue Pages 104-108
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract This study presents first-principles results on the electronic functionalization of silicene and germanene monolayers by means of chemisorption of adatom species H, Li, F, Sc, Ti, V. Three general adatom-monolayer configurations are considered, each having its distinct effect on the electronic structure, yielding metallic or semiconducting dispersions depending on the adatom species and configuration. The induced bandgap is a (in)direct F gap ranging from 0.2 to 2.3 eV for both silicene and germanene. In general the alternating configuration was found to be the most energetically stable. The boatlike and chairlike conformers are degenerate with the former having anisotropic effective carrier masses. The top configuration leads to the planar monolayer and predominately to a gapped dispersion. The hollow configuration with V adatoms retains the Dirac cone, but with strong orbital planar hybridization at the Fermi level. We also observe a planar surface state the Fermi level for the latter systems. (C) 2013 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000329327700023 Publication Date 2013-09-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0169-4332; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 3.387 Times cited 32 Open Access
Notes Approved Most recent IF: 3.387; 2014 IF: 2.711
Call Number UA @ lucian @ c:irua:113766 Serial 1208
Permanent link to this record
 
 
Author Houssa, M.; van den Broek, B.; Scalise, E.; Ealet, B.; Pourtois, G.; Chiappe, D.; Cinquanta, E.; Grazianetti, C.; Fanciulli, M.; Molle, A.; Afanas’ev, V.V.; Stesmans, A.;
Title Theoretical aspects of graphene-like group IV semiconductors Type A1 Journal article
Year 2014 Publication Applied surface science Abbreviated Journal Appl Surf Sci
Volume 291 Issue Pages 98-103
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Silicene and germanene are the silicon and germanium counterparts of graphene, respectively. Recent experimental works have reported the growth of silicene on (1 1 1)Ag surfaces with different atomic configurations, depending on the growth temperature and surface coverage. We first theoretically study the structural and electronic properties of silicene on (1 1 1) Ag surfaces, focusing on the (4 x 4) silicene/Ag structure. Due to symmetry breaking in the silicene layer (nonequivalent number of top and bottom Si atoms), the corrugated silicene layer, with the Ag substrate removed, is predicted to be semiconducting, with a computed energy bandgap of about 0.3 eV. However, the hybridization between the Si 3p orbitals and the Ag 5s orbital in the silicene/(1 1 1)Ag slab model leads to an overall metallic system, with a distribution of local electronic density of states, which is related to the slightly disordered structure of the silicene layer on the (1 1 1)Ag surface. We next study the interaction of silicene and germanene with different hexagonal non-metallic substrates, namely ZnS and ZnSe. On reconstructed (0 0 0 1)ZnS or ZnSe surfaces, which should be more energetically stable for very thin layers, silicene and germanene are found to be semiconducting. Remarkably, the nature and magnitude of their energy bandgap can be controlled by an out-of-plane electric field, an important finding for the potential use of these materials in nanoelectronic devices. (C) 2013 Elsevier B. V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000329327700022 Publication Date 2013-09-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0169-4332; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 3.387 Times cited 20 Open Access
Notes Approved Most recent IF: 3.387; 2014 IF: 2.711
Call Number UA @ lucian @ c:irua:113765 Serial 3603
Permanent link to this record
 
 
Author Scalise, E.; Cinquanta, E.; Houssa, M.; van den Broek, B.; Chiappe, D.; Grazianetti, C.; Pourtois, G.; Ealet, B.; Molle, A.; Fanciulli, M.; Afanas’ev, V.V.; Stesmans, A.;
Title Vibrational properties of epitaxial silicene layers on (111) Ag Type A1 Journal article
Year 2014 Publication Applied surface science Abbreviated Journal Appl Surf Sci
Volume 291 Issue Pages 113-117
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The electronic and vibrational properties of three different reconstructions of silicene on Ag(1 1 1) are calculated and compared to experimental results. The 2D epitaxial silicon layers, namely the (4 x 4), (root 13 x root 13) and (2 root 3 x 2 root 3) phases, exhibit different electronic and vibrational properties. Few peaks in the experimental Raman spectrum are identified and attributed to the vibrational modes of the silicene layers. The position and behavior of the Raman peaks with respect to the excitation energy are shown to be a fundamental tool to investigate and discern different phases of silicene on Ag( 1 1 1). (C) 2013 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000329327700025 Publication Date 2013-09-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0169-4332; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 3.387 Times cited 36 Open Access
Notes Approved Most recent IF: 3.387; 2014 IF: 2.711
Call Number UA @ lucian @ c:irua:113767 Serial 3843
Permanent link to this record
 
 
Author Houssa, M.; Scalise, E.; Sankaran, K.; Pourtois, G.; Afanas'ev, V.V.; Stesmans, A.
Title Electronic properties of hydrogenated silicene and germanene Type A1 Journal article
Year 2011 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 98 Issue 22 Pages 223107
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The electronic properties of hydrogenated silicene and germanene, so called silicane and germanane, respectively, are investigated using first-principles calculations based on density functional theory. Two different atomic configurations are found to be stable and energetically degenerate. Upon the adsorption of hydrogen, an energy gap opens in silicene and germanene. Their energy gaps are next computed using the HSE hybrid functional as well as the G(0)W(0) many-body perturbation method. These materials are found to be wide band-gap semiconductors, the type of gap in silicane (direct or indirect) depending on its atomic configuration. Germanane is predicted to be a direct-gap material, independent of its atomic configuration, with an average energy gap of about 3.2 eV, this material thus being potentially interesting for optoelectronic applications in the blue/violet spectral range. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3595682]
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000291405700057 Publication Date 2011-06-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 3.411 Times cited 63 Open Access
Notes Approved Most recent IF: 3.411; 2011 IF: 3.844
Call Number UA @ lucian @ c:irua:105586 Serial 1003
Permanent link to this record
 
 
Author Houssa, M.; Pourtois, G.; Afanas'ev, V.V.; Stesmans, A.
Title Electronic properties of two-dimensional hexagonal germanium Type A1 Journal article
Year 2010 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 96 Issue 8 Pages 082111,1-082111,3
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The electronic properties of two-dimensional hexagonal germanium, so called germanene, are investigated using first-principles simulations. Consistent with previous reports, the surface is predicted to have a poor metallic behavior, i.e., being metallic with a low density of states at the Fermi level. It is found that biaxial compressively strained germanene is a gapless semiconductor with linear energy dispersions near the K pointslike graphene. The calculated Fermi velocity of germanene is almost independent of the strain and is about 1.7×10<sup>6</sup> m/s, quite comparable to the value in graphene.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000275027200044 Publication Date 2010-02-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 3.411 Times cited 86 Open Access
Notes Approved Most recent IF: 3.411; 2010 IF: 3.841
Call Number UA @ lucian @ c:irua:91716 Serial 1004
Permanent link to this record
 
 
Author Sankaran, K.; Pourtois, G.; Degraeve, R.; Zahid, M.B.; Rignanese, G.-M.; Van Houdt, J.
Title First-principles modeling of intrinsic and extrinsic defects in \gamma-Al2O3 Type A1 Journal article
Year 2010 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 97 Issue 21 Pages 212906
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The electronic properties of a set of intrinsic and extrinsic point defects in gamma-Al2O3 are investigated using quasiparticle calculations within the G(0)W(0) approximation. We find that the electronic signature of atomic vacancies lie deep in the band gap, close to the top of the valence band edge. The introduction of C, Si, and N impurities induces defective levels that are located close to the conduction band edge and near the middle of the band gap of the oxide. The comparison with electrical measurements reveals that the energy levels of some of these defects match with the electronic fingerprint of the defects reported in gamma-Al2O3 based nonvolatile memories. (C) 2010 American Institute of Physics. [doi:10.1063/1.3507385]
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000284618300039 Publication Date 2010-11-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 3.411 Times cited 12 Open Access
Notes Approved Most recent IF: 3.411; 2010 IF: 3.841
Call Number UA @ lucian @ c:irua:105617 Serial 1213
Permanent link to this record
 
 
Author Clima, S.; Chen, Y.Y.; Degraeve, R.; Mees, M.; Sankaran, K.; Govoreanu, B.; Jurczak, M.; De Gendt, S.; Pourtois, G.
Title First-principles simulation of oxygen diffusion in HfOx : role in the resistive switching mechanism Type A1 Journal article
Year 2012 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 100 Issue 13 Pages 133102-133102,4
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Transition metal oxide-based resistor random access memory (RRAM) takes advantage of oxygen-related defects in its principle of operation. Since the change in resistivity of the material is controlled by the oxygen deficiency level, it is of major importance to quantify the kinetics of the oxygen diffusion, key factor for oxide stoichiometry. Ab initio accelerated molecular dynamics techniques are employed to investigate the oxygen diffusivity in amorphous hafnia (HfOx, x = 1.97, 1.0, 0.5). The computed kinetics is in agreement with experimental measurements. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3697690]
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000302230800060 Publication Date 2012-03-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 3.411 Times cited 63 Open Access
Notes Approved Most recent IF: 3.411; 2012 IF: 3.794
Call Number UA @ lucian @ c:irua:97786 Serial 1214
Permanent link to this record
 
 
Author Clima, S.; Wouters, D.J.; Adelmann, C.; Schenk, T.; Schroeder, U.; Jurczak, M.; Pourtois, G.
Title Identification of the ferroelectric switching process and dopant-dependent switching properties in orthorhombic HfO2 : a first principles insight Type A1 Journal article
Year 2014 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 104 Issue 9 Pages 092906
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The origin of the ferroelectric polarization switching in orthorhombic HfO2 has been investigated by first principles calculations. The phenomenon can be regarded as being the coordinated displacement of four O ions in the orthorhombic unit cell, which can lead to a saturated polarization as high as 53 mu C/cm(2). We show the correlation between the computed polarization reversal barrier and the experimental coercive fields. (C) 2014 AIP Publishing LLC.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000332729200078 Publication Date 2014-03-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951;1077-3118; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 3.411 Times cited 79 Open Access
Notes Approved Most recent IF: 3.411; 2014 IF: 3.302
Call Number UA @ lucian @ c:irua:116873 Serial 1550
Permanent link to this record
 
 
Author Scalise, E.; Houssa, M.; Pourtois, G.; Afanas'ev, V.V.; Stesmans, A.
Title Inelastic electron tunneling spectroscopy of HfO2 gate stacks : a study based on first-principles modeling Type A1 Journal article
Year 2011 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 99 Issue 13 Pages 132101,1-132101,3
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract A first-principles modeling approach is used to investigate the vibrational properties of HfO2. The calculated phonon density of states is compared to experimental results obtained from inelastic electron tunneling spectroscopy (IETS) of various metal-oxide-semiconductor devices with HfO2 gate stacks. This comparison provides deep insights into the nature of the signatures of the complicated IETS spectra and provides valuable structural information about the gate stack, such as the possible presence of oxygen vacancies in jet-vapour deposited HfO2. Important structural differences between the interface of atomic-layer or molecular-beam deposited HfO2 and the Si substrate are also revealed.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000295618000036 Publication Date 2011-09-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 3.411 Times cited 1 Open Access
Notes Approved Most recent IF: 3.411; 2011 IF: 3.844
Call Number UA @ lucian @ c:irua:93611 Serial 1606
Permanent link to this record
 
 
Author Chen, Y.Y.; Pourtois, G.; Adelmann, C.; Goux, L.; Govoreanu, B.; Degreave, R.; Jurczak, M.; Kittl, J.A.; Groeseneken, G.; Wouters, D.J.
Title Insights into Ni-filament formation in unipolar-switching Ni/HfO2/TiN resistive random access memory device Type A1 Journal article
Year 2012 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 100 Issue 11 Pages 113513-113513,4
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this letter, CMOS-compatible Ni/HfO2/TiN resistive random access memory stacks demonstrated attractive unipolar switching properties, showing >10(3) endurance and long retention at 150 degrees C. The Ni bottom electrode (BE) improved the switching yield over the NiSiPt BE. To better understand the unipolar forming mechanism, ab initio simulation and time of flight-secondary ion mass spectroscopy were utilized. Compared to the NiSiPt BE, Ni BE gives larger Ni diffusion in the HfO2 and lower formation enthalpy of Ni2+ species during electrical forming. Both the electrical and physical results supported a Ni-injection mechanism for the filament formation. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3695078]
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000302204900091 Publication Date 2012-03-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-6951; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 3.411 Times cited 29 Open Access
Notes Approved Most recent IF: 3.411; 2012 IF: 3.794
Call Number UA @ lucian @ c:irua:98295 Serial 1674
Permanent link to this record