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| Author | Khalilov, U.; Bogaerts, A.; Neyts, E.C. | ||||
| 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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| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Editor | |||
| Language | Wos | 000399859800016 | Publication Date | 2017-04-18 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| 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 | ||
| Permanent link to this record | |||||
| Author | Ostrikov, K.; Neyts, E.C.; Meyyappan, M. | ||||
| Title | Plasma nanoscience : from nano-solids in plasmas to nano-plasmas in solids | Type | A1 Journal article | ||
| Year | 2013 | Publication | Advances in physics | Abbreviated Journal | Adv Phys |
| Volume | 62 | Issue | 2 | Pages | 113-224 |
| Keywords | A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
| Abstract | The unique plasma-specific features and physical phenomena in the organization of nanoscale soild-state systems in a broad range of elemental composition, structure, and dimensionality are critically reviewed. These effects lead to the possibility to localize and control energy and matter at nanoscales and to produce self-organized nano-solids with highly unusual and superior properties. A unifying conceptual framework based on the control of production, transport, and self-organization of precursor species is introduced and a variety of plasma-specific non-equilibrium and kinetics-driven phenomena across the many temporal and spatial scales is explained. When the plasma is localized to micrometer and nanometer dimensions, new emergent phenomena arise. The examples range from semiconducting quantum dots and nanowires, chirality control of single-walled carbon nanotubes, ultra-fine manipulation of graphenes, nano-diamond, and organic matter to nano-plasma effects and nano-plasmas of different states of matter. | ||||
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| Publisher | Place of Publication | London | Editor | ||
| Language | Wos | 000320913600001 | Publication Date | 2013-06-18 | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0001-8732;1460-6976; | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor |
21.818 | Times cited | 380 | Open Access | |
| Notes | Approved | Most recent IF: 21.818; 2013 IF: 18.062 | |||
| Call Number | UA @ lucian @ c:irua:108723 | Serial | 2639 | ||
| Permanent link to this record | |||||
| Author | Neyts, E.C.; Ostrikov, K.K.; Sunkara, M.K.; Bogaerts, A. | ||||
| Title | Plasma Catalysis: Synergistic Effects at the Nanoscale | Type | A1 Journal article | ||
| Year | 2015 | Publication | Chemical reviews | Abbreviated Journal | Chem Rev |
| Volume | 115 | Issue | 115 | Pages | 13408-13446 |
| Keywords | A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) | ||||
| Abstract | Thermal-catalytic gas processing is integral to many current industrial processes. Ever-increasing demands on conversion and energy efficiencies are a strong driving force for the development of alternative approaches. Similarly, synthesis of several functional materials (such as nanowires and nanotubes) demands special processing conditions. Plasma catalysis provides such an alternative, where the catalytic process is complemented by the use of plasmas that activate the source gas. This combination is often observed to result in a synergy between plasma and catalyst. This Review introduces the current state-of-the-art in plasma catalysis, including numerous examples where plasma catalysis has demonstrated its benefits or shows future potential, including CO2 conversion, hydrocarbon reforming, synthesis of nanomaterials, ammonia production, and abatement of toxic waste gases. The underlying mechanisms governing these applications, as resulting from the interaction between the plasma and the catalyst, render the process highly complex, and little is known about the factors leading to the often-observed synergy. This Review critically examines the catalytic mechanisms relevant to each specific application. | ||||
| Address | Department of Chemistry, Research Group PLASMANT, Universiteit Antwerpen , Universiteitsplein 1, 2610 Wilrijk-Antwerp, Belgium | ||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Editor | |||
| Language | English | Wos | 000367563000006 | Publication Date | 2015-11-30 |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 0009-2665 | ISBN | Additional Links | UA library record; WoS full record; WoS citing articles | |
| Impact Factor |
47.928 | Times cited | 204 | Open Access | |
| Notes | ECN and AB gratefully acknowledge financial support from the Fund of Scientific Research Flanders (FWO), Belgium, Grant Number G.0217.14N. KO acknowledges partial support by the Australian Research Council and CSIRO’s OCE Science Leaders Program. MKS acknowledges partial support from US National Science Foundation through grants DMS 1125909 and EPSCoR 1355448 and also PhD students Babajide Ajayi, Apolo Nambo and Maria Carreon for their help. | Approved | Most recent IF: 47.928; 2015 IF: 46.568 | ||
| Call Number | c:irua:130001 | Serial | 3993 | ||
| Permanent link to this record | |||||