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Author Sankaran, K.; Swerts, J.; Couet, S.; Stokbro, K.; Pourtois, G.
Title (down) Oscillatory behavior of the tunnel magnetoresistance due to thickness variations in Ta vertical bar CoFe vertical bar MgO magnetic tunnel junctions : a first-principles study Type A1 Journal article
Year 2016 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 94 Issue 94 Pages 094424
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract To investigate the impact of both the CoFe ferromagnetic layer thickness and the capping paramagnetic layer on the tunnel magnetoresistance (TMR), we performed first-principles simulations on epitaxial magnetic tunnel junctions contacted with either CoFe or Ta paramagnetic capping layers. We observed a strong oscillation of the TMR amplitude with respect to the thickness of the ferromagnetic layer. The TMR is found to be amplified whenever the MgO spin tunnel barrier is thickened. Quantization of the electronic structure of the ferromagnetic layers is found to be at the origin of this oscillatory behavior. Metals such as Ta contacting the magnetic layer are found to enhance the amplitude of the oscillations due to the occurrence of an interface dipole. The latter drives the band alignment and tunes the nature of the spin channels that are active during the tunneling process. Subsequently, the regular transmission spin channels are modulated in the magnetic tunnel junction stack and other complex ones are being activated.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000383860700004 Publication Date 2016-09-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9950;2469-9969; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 4 Open Access
Notes Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:137122 Serial 4468
Permanent link to this record
 
 
Author Lu, A.K.A.; Pourtois, G.; Agarwal, T.; Afzalian, A.; Radu, I.P.; Houssa, M.
Title (down) Origin of the performances degradation of two-dimensional-based metal-oxide-semiconductor field effect transistors in the sub-10 nm regime: A first-principles study Type A1 Journal article
Year 2016 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 108 Issue 4 Pages 043504
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The impact of the scaling of the channel length on the performances of metal-oxide-semiconductor field effect transistors, based on two-dimensional (2D) channel materials, is theoretically investigated, using density functional theory combined with the non-equilibrium Green's function method. It is found that the scaling of the channel length below 10nm leads to strong device performance degradations. Our simulations reveal that this degradation is essentially due to the tunneling current flowing between the source and the drain in these aggressively scaled devices. It is shown that this electron tunneling process is modulated by the effective mass of the 2D channel material, and sets the limit of the scaling in future transistor designs. (C) 2016 AIP Publishing LLC.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000375217200061 Publication Date 2016-01-26
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 3.411 Times cited 4 Open Access
Notes Approved Most recent IF: 3.411
Call Number UA @ lucian @ c:irua:144750 Serial 4677
Permanent link to this record
 
 
Author de de Meux, A.J.; Pourtois, G.; Genoe, J.; Heremans, P.
Title (down) 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 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 Dhayalan, S.K.; Kujala, J.; Slotte, J.; Pourtois, G.; Simoen, E.; Rosseel, E.; Hikavyy, A.; Shimura, Y.; Iacovo, S.; Stesmans, A.; Loo, R.; Vandervorst, W.;
Title (down) On the manifestation of phosphorus-vacancy complexes in epitaxial Si:P films Type A1 Journal article
Year 2016 Publication Applied physics letters Abbreviated Journal Appl Phys Lett
Volume 108 Issue 108 Pages 082106
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In situ doped epitaxial Si: P films with P concentrations > 1 x 10(21) at./cm(3) are suitable for source-drain stressors of n-FinFETs. These films combine the advantages of high conductivity derived from the high P doping with the creation of tensile strain in the Si channel. It has been suggested that the tensile strain developed in the Si: P films is due to the presence of local Si3P4 clusters, which however do not contribute to the electrical conductivity. During laser annealing, the Si3P4 clusters are expected to disperse resulting in an increased conductivity while the strain reduces slightly. However, the existence of Si3P4 is not proven. Based on first-principles simulations, we demonstrate that the formation of vacancy centered Si3P4 clusters, in the form of four P atoms bonded to a Si vacancy, is thermodynamically favorable at such high P concentrations. We suggest that during post epi-growth annealing, a fraction of the P atoms from these clusters are activated, while the remaining part goes into interstitial sites, thereby reducing strain. We corroborate our conjecture experimentally using positron annihilation spectroscopy, electron spin resonance, and Rutherford backscattering ion channeling studies. (C) 2016 AIP Publishing LLC.
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Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000373057000023 Publication Date 2016-02-24
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 3.411 Times cited 9 Open Access
Notes Approved Most recent IF: 3.411
Call Number UA @ lucian @ c:irua:133245 Serial 4217
Permanent link to this record
 
 
Author Dhayalan, S.K.; Kujala, J.; Slotte, J.; Pourtois, G.; Simoen, E.; Rosseel, E.; Hikavyy, A.; Shimura, Y.; Loo, R.; Vandervorst, W.
Title (down) On the evolution of strain and electrical properties in as-grown and annealed Si:P epitaxial films for source-drain stressor applications Type A1 Journal article
Year 2018 Publication ECS journal of solid state science and technology Abbreviated Journal Ecs J Solid State Sc
Volume 7 Issue 5 Pages P228-P237
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Heavily P doped Si:P epitaxial layers have gained interest in recent times as a promising source-drain stressor material for n type FinFETs (Fin Field Effect Transistors). They are touted to provide excellent conductivity as well as tensile strain. Although the as-grown layers do provide tensile strain, their conductivity exhibits an unfavorable behavior. It reduces with increasing P concentration (P > 1E21 at/cm(3)), accompanied by a saturation in the active carrier concentration. Subjecting the layers to laser annealing increases the conductivity and activates a fraction of P atoms. However, there is also a concurrent reduction in tensile strain (<1%). Literature proposes the formation of local semiconducting Si3P4 complexes to explain the observed behaviors in Si:P [Z. Ye et al., ECS Trans., 50(9) 2013, p. 1007-10111. The development of tensile strain and the saturation in active carrier is attributed to the presence of local complexes while their dispersal on annealing is attributed to strain reduction and increase in active carrier density. However, the existence of such local complexes is not proven and a fundamental void exists in understanding the structure-property correlation in Si:P films. In this respect, our work investigates the reason behind the evolution of strain and electrical properties in the as-grown and annealed Si:P epitaxial layers using ab-initio techniques and corroborate the results with physical characterization techniques. It will be shown that the strain developed in Si:P films is not due to any specific complexes while the formation of Phosphorus-vacancy complexes will be shown responsible for the carrier saturation and the increase in resistivity in the as-grown films. Interstitial/precipitate formation is suggested to be a reason for the strain loss in the annealed films. (C) The Author(s) 2018. Published by ECS.
Address
Corporate Author Thesis
Publisher Electrochemical society Place of Publication Pennington (N.J.) Editor
Language Wos 000440834200010 Publication Date 2018-05-01
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 1.787 Times cited 4 Open Access OpenAccess
Notes Approved Most recent IF: 1.787
Call Number UA @ lucian @ c:irua:153204 Serial 5122
Permanent link to this record
 
 
Author Lu, A.K.A.; Pourtois, G.; Luisier, M.; Radu, I.P.; Houssa, M.
Title (down) On the electrostatic control achieved in transistors based on multilayered MoS2 : a first-principles study Type A1 Journal article
Year 2017 Publication Journal of applied physics Abbreviated Journal
Volume 121 Issue 4 Pages 044505
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract In this work, the electrostatic control in metal-oxide-semiconductor field-effect transistors based on MoS2 is studied, with respect to the number of MoS2 layers in the channel and to the equivalent oxide thickness of the gate dielectric, using first-principles calculations combined with a quantum transport formalism. Our simulations show that a compromise exists between the drive current and the electrostatic control on the channel. When increasing the number of MoS2 layers, a degradation of the device performances in terms of subthreshold swing and OFF currents arises due to the screening of the MoS2 layers constituting the transistor channel. Published by AIP Publishing.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000393480100030 Publication Date 2017-01-26
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 Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:152673 Serial 8329
Permanent link to this record
 
 
Author Khalilov, U.; Pourtois, G.; van Duin, A.C.T.; Neyts, E.C.
Title (down) On the c-Si\mid a-SiO2 interface in hyperthermal Si oxidation at room 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 41 Pages 21856-21863
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000309902100026 Publication Date 2012-09-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 27 Open Access
Notes Approved Most recent IF: 4.536; 2012 IF: 4.814
Call Number UA @ lucian @ c:irua:102167 Serial 2458
Permanent link to this record
 
 
Author Sorée, B.; Magnus, W.; Szepieniec, M.; Vandenbreghe, W.; Verhulst, A.; Pourtois, G.; Groeseneken, G.; de Gendt, S.; Heyns, M.
Title (down) Novel device concepts for nanotechnology : the nanowire pinch-off FET and graphene tunnelFET Type A2 Journal article
Year 2010 Publication ECS transactions Abbreviated Journal
Volume 28 Issue Pages 15-26
Keywords A2 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract We explain the basic operation of a nanowire pinch-off FET and graphene nanoribbon tunnelFET. For the nanowire pinch-off FET we construct an analytical model to obtain the threshold voltage as a function of radius and doping density. We use the gradual channel approximation to calculate the current-voltage characteristics of this device and we show that the nanowire pinch-off FET has a subthreshold slope of 60 mV/dec and good ION and ION/IOFF ratios. For the graphene nanoribbon tunnelFET we show that an improved analytical model yields more realistic results for the transmission probability and hence the tunneling current. The first simulation results for the graphene nanoribbon tunnelFET show promising subthreshold slopes.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1938-5862 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:89510 Serial 2375
Permanent link to this record
 
 
Author Khalilov, U.; Pourtois, G.; Huygh, S.; van Duin, A.C.T.; Neyts, E.C.; Bogaerts, A.
Title (down) 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
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000319649100032 Publication Date 2013-04-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
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
Call Number UA @ lucian @ c:irua:107989 Serial 2321
Permanent link to this record
 
 
Author de de Meux, A.J.; Pourtois, G.; Genoe, J.; Heremans, P.
Title (down) Method to quantify the delocalization of electronic states in amorphous semiconductors and its application to assessing charge carrier mobility of p-type amorphous oxide semiconductors Type A1 Journal article
Year 2018 Publication Physical review B Abbreviated Journal Phys Rev B
Volume 97 Issue 4 Pages 045208
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Amorphous semiconductors are usually characterized by a low charge carrier mobility, essentially related to their lack of long-range order. The development of such material with higher charge carrier mobility is hence challenging. Part of the issue comes from the difficulty encountered by first-principles simulations to evaluate concepts such as the electron effective mass for disordered systems since the absence of periodicity induced by the disorder precludes the use of common concepts derived from condensed matter physics. In this paper, we propose a methodology based on first-principles simulations that partially solves this problem, by quantifying the degree of delocalization of a wave function and of the connectivity between the atomic sites within this electronic state. We validate the robustness of the proposed formalism on crystalline and molecular systems and extend the insights gained to disordered/amorphous InGaZnO4 and Si. We also explore the properties of p-type oxide semiconductor candidates recently reported to have a low effective mass in their crystalline phases [G. Hautier et al., Nat. Commun. 4, 2292 (2013)]. Although in their amorphous phase none of the candidates present a valence band with delocalization properties matching those found in the conduction band of amorphous InGaZnO4, three of the seven analyzed materials show some potential. The most promising candidate, K2Sn2O3, is expected to possess in its amorphous phase a slightly higher hole mobility than the electron mobility in amorphous silicon.
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication New York, N.Y Editor
Language Wos 000423427600005 Publication Date 2018-01-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 2 Open Access OpenAccess
Notes Approved Most recent IF: 3.836
Call Number UA @ lucian @ c:irua:149318 Serial 4943
Permanent link to this record
 
 
Author Sankaran, K.; Moors, K.; Dutta, S.; Adelmann, C.; Tokei, Z.; Pourtois, G.
Title (down) Metallic ceramics for low resitivity interconnects : an ab initio insight Type P1 Proceeding
Year 2018 Publication Proceedings of the IEEE ... International Interconnect Technology Conference T2 – IEEE International Interconnect Technology Conference (IITC), JUN 04-07, 2018, Santa Clara, CA Abbreviated Journal
Volume Issue Pages 160-162
Keywords P1 Proceeding; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract The scalability potential of low resistivity ternary metallic alloys (MAX) as an interconnect medium has been benchmarked against copper through first-principle simulations. We report that some carbon and nitrogen MAX phases have the potential to display a reduced sensitivity of their intrinsic resistivity to scaling, while showing improved electromigration properties.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000468672900053 Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-1-5386-4337-2; 978-1-5386-4337-2 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved no
Call Number UA @ admin @ c:irua:160474 Serial 8219
Permanent link to this record
 
 
Author Delabie, A.; Sioncke, S.; Rip, J.; van Elshocht, S.; Caymax, M.; Pourtois, G.; Pierloot, K.
Title (down) Mechanisms for the trimethylaluminum reaction in aluminum oxide atomic layer deposition on sulfur passivated germanium Type A1 Journal article
Year 2011 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 115 Issue 35 Pages 17523-17532
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Germanium combined with high-κ dielectrics is investigated for the next generations of CMOS devices. Therefore, we study reaction mechanisms for Al2O3 atomic layer deposition on sulfur passivated Ge using calculations based on density functional theory and total reflection X-ray fluorescence (TXRF). TXRF indicates 6 S/nm2 and 4 Al/nm2 after the first TMA/H2O reaction cycle, and growth inhibition from the second reaction cycle on. Calculations are performed on molecular clusters representing −GeSH surface sites. The calculations confirm that the TMA reaction does not affect the S content. On fully SH-terminated Ge, TMA favorably reacts with up to three −GeSH sites, resulting in a near tetrahedral Al coordination. Electron deficient structures with a GeS site shared between two Al atoms are proposed. The impact of the cluster size on the structures and reaction energetics is systematically investigated.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000294386000037 Publication Date 2011-08-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 9 Open Access
Notes Approved Most recent IF: 4.536; 2011 IF: 4.805
Call Number UA @ lucian @ c:irua:91714 Serial 1980
Permanent link to this record
 
 
Author Clima, S.; Garbin, D.; Devulder, W.; Keukelier, J.; Opsomer, K.; Goux, L.; Kar, G.S.; Pourtois, G.
Title (down) 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 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 Nishio, K.; Lu, A.K.A.; Pourtois, G.
Title (down) Low-strain Si/O superlattices with tunable electronic properties : ab initio calculations Type A1 Journal article
Year 2015 Publication Physical review : B : condensed matter and materials physics Abbreviated Journal Phys Rev B
Volume 91 Issue 91 Pages 165303
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract We propose that low-strain Si/O superlattices can be constructed by connecting reconstructed Si{001} surfaces by Si-O-Si bridges. Ab initio calculations show that our models are energetically more favorable than all the models proposed so far. The part of our Si/O superlattice model is experimentally accessible just by oxidizing a Si( 001) substrate. To complete our Si/O superlattice model, we propose a three-step method. We also explore the potential of our Si/O superlattice models for new materials used in future Si electronics. We find that the location of the channel where the carriers travel can be controlled between the interfaces and the Si layers by the insertion of O atoms into the Si-Si dimers. By revealing the origins of the interface electron and hole states, we find that similar interface states should be easily achieved for Si slabs and Si substrates. Interestingly, the interface electrons and holes have small effective masses in the direction parallel to the channel and large effective masses in the direction normal to the channel, which makes the Si/O superlattices attractive to be used for channel materials. We also find that the valley splitting of Si is enhanced by the formation of the Si/O/Si interfaces, which is ideal for developing Si-based qubits. Our findings open new perspectives to design and control the electronic properties of Si.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000352986700002 Publication Date 2015-04-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1098-0121;1550-235X; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.836 Times cited 6 Open Access
Notes Approved Most recent IF: 3.836; 2015 IF: 3.736
Call Number c:irua:125998 Serial 1852
Permanent link to this record
 
 
Author Clima, S.; Belmonte, A.; Degraeve, R.; Fantini, A.; Goux, L.; Govoreanu, B.; Jurczak, M.; Ota, K.; Redolfi, A.; Kar, G.S.; Pourtois, G.
Title (down) Kinetic and thermodynamic heterogeneity : an intrinsic source of variability in Cu-based RRAM memories Type A1 Journal article
Year 2017 Publication Journal of computational electronics Abbreviated Journal J Comput Electron
Volume 16 Issue 4 Pages 1011-1016
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract <script type='text/javascript'>document.write(unpmarked('The resistive random-access memory (RRAM) device concept is close to enabling the development of a new generation of non-volatile memories, provided that their reliability issues are properly understood. The design of a RRAM operating with extrinsic defects based on metallic inclusions, also called conductive bridge RAM, allows the use of a large spectrum of solid electrolytes. However, when scaled to device dimensions that meet the requirements of the latest technological nodes, the discrete nature of the atomic structure of the materials impacts the device operation. Using density functional theory simulations, we evaluated the migration kinetics of Cu conducting species in amorphous and solid electrolyte materials, and established that atomic disorder leads to a large variability in terms of defect stability and kinetic barriers. This variability has a significant impact on the filament resistance and its dynamics, as evidenced during the formation step of the resistive filament. Also, the atomic configuration of the formed filament can age/relax to another metastable atomic configuration, and lead to a modulation of the resistivity of the filament. All these observations are qualitatively explained on the basis of the computed statistical distributions of the defect stability and on the kinetic barriers encountered in RRAM materials.'));
Address
Corporate Author Thesis
Publisher Place of Publication Place of publication unknown Editor
Language Wos 000417598100004 Publication Date 2017-08-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1569-8025 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 1.526 Times cited 2 Open Access Not_Open_Access
Notes Approved Most recent IF: 1.526
Call Number UA @ lucian @ c:irua:148569 Serial 4883
Permanent link to this record
 
 
Author Clima, S.; Chen, Y.Y.; Fantini, A.; Goux, L.; Degraeve, R.; Govoreanu, B.; Pourtois, G.; Jurczak, M.
Title (down) 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 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 Dhayalan, S.K.; Nuytten, T.; Pourtois, G.; Simoen, E.; Pezzoli, F.; Cinquanta, E.; Bonera, E.; Loo, R.; Rosseel, E.; Hikavyy, A.; Shimura, Y.; Vandervorst, W.
Title (down) Insights into the C Distribution in Si:C/Si:C:P and the Annealing Behavior of Si:C Layers Type A1 Journal article
Year 2019 Publication ECS journal of solid state science and technology Abbreviated Journal Ecs J Solid State Sc
Volume 8 Issue 4 Pages P209-P216
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Si:C and Si:C:P alloys are potential candidates for source-drain stressor applications in n-type Fin Field Effect Transistors (FinFETs). Increasing the C content to achieve high strain results in the arrangement of C atoms as third nearest neighbors (3nn) in the Si: C lattice. During thermal annealing, the presence of C atoms as 3nn may promote clustering at the interstitial sites, causing loss of stress. The concentration of C atoms as 3nn is reduced by the incorporation of a small amount of Ge atoms during the growth, whereas in-situ P doping does not influence this 3nn distribution [J Solid State Sci. Technol vol 6, p 755, 2017]. Small amounts of Ge are provided during low temperature selective epitaxial growth scheme, which are based on cyclic deposition and etching (CDE). In this work, we aim to provide physical insights into the aforementioned phenomena, to understand the behavior of 3nn C atoms and the types of defects that are formed in the annealed Si: C films. Using ab-initio simulations, the Ge-C interaction in the Si matrix is investigated and this insight is used to explain how the Ge incorporation leads to a reduced 3nn distribution of the C atoms. The interaction between C and P in the Si: C: P films is also investigated to explain why the P incorporation has not led to a reduction in the 3nn distribution. We then report on the Raman characterization of Si: C layers subjected to post epi annealing. As the penetration depth of the laser is dependent on the wavelength, Raman measurements at two different wavelengths enable us to probe the depth distribution of 3nn C atoms after applying different annealing conditions. We observed a homogeneous loss in 3nn C throughout the layer. Whereas in the kinematic modeling of high resolution X-ray diffraction spectra, a gradient in the substitutional C loss was observed close to the epitaxial layer/substrate interface. This gradient can be due to the out diffusion of C atoms into the Si substrate or to the formation of interstitial C clusters, which cannot be distinguished in HR-XRD. Deep Level Transient Spectroscopy indicated that the prominent out-diffusing species was interstitial CO complex while the interstitial C defects were also prevalent in the epi layer. (c) 2019 The Electrochemical Society.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000465069200001 Publication Date 2019-04-18
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
Impact Factor 1.787 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 1.787
Call Number UA @ admin @ c:irua:160399 Serial 5275
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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 (down) 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 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
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Author Scalise, E.; Houssa, M.; Pourtois, G.; Afanas'ev, V.V.; Stesmans, A.
Title (down) 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 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
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Author Lu, A.K.A.; Houssa, M.; Luisier, M.; Pourtois, G.
Title (down) Impact of layer alignment on the behavior of MoS2-ZrS2 tunnel field-effect transistors : an ab initio study Type A1 Journal article
Year 2017 Publication Physical review applied Abbreviated Journal Phys Rev Appl
Volume 8 Issue 3 Pages 034017
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Tunnel field-effect transistors based on van der Waals heterostructures are emerging device concepts for low-power applications, auguring sub-60 mV/dec subthreshold swing values. In these devices, the channel is built from a stack of several different two-dimensional materials whose nature allows tailoring the band alignments and enables a good electrostatic control of the device. In this work, we propose a theoretical study of the variability of the performances of a MoS2-ZrS2 tunnel field-effect transistor induced by fluctuations of the relative position or the orientation of the layers. Our results indicate that although a steep subthreshold slope (20 mV/dec) is achievable, fluctuations in the relative orientation of the ZrS2 layer with respect to the MoS2 one lead to a significant variability in the tunneling current by about one decade. This arises from changes in the orbital overlap between the layers and from the modulation of the transport direction.
Address
Corporate Author Thesis
Publisher American Physical Society Place of Publication College Park, Md Editor
Language Wos 000411460400001 Publication Date 2017-09-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2331-7019 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.808 Times cited 6 Open Access OpenAccess
Notes Approved Most recent IF: 4.808
Call Number UA @ lucian @ c:irua:146741 Serial 4785
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Author Guo, J.; Clima, S.; Pourtois, G.; Van Houdt, J.
Title (down) Identifying alternative ferroelectric materials beyond Hf(Zr)O-₂ Type A1 Journal article
Year 2020 Publication Applied Physics Letters Abbreviated Journal Appl Phys Lett
Volume 117 Issue 26 Pages 262903
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract A database-driven approach combined with ab initio density functional theory (DFT) simulations is used to identify and simulate alternative ferroelectric materials beyond Hf(Zr)O-2. The database-driven screening method identifies a class of wurtzite ferroelectric materials. DFT simulations of wurtzite magnesium chalcogenides, including MgS, MgSe, and MgTe, show their potential to achieve improved ferroelectric (FE) stability, simple atomistic unit cell structure, and large FE polarization. Strain engineering can effectively modulate the FE switching barrier height for facilitating FE switching. The effect of the piezoelectric property on the FE switching barrier heights is also examined.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000608049700003 Publication Date 2020-12-28
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 4 Times cited Open Access
Notes Approved Most recent IF: 4; 2020 IF: 3.411
Call Number UA @ admin @ c:irua:176053 Serial 6766
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Author Clima, S.; Wouters, D.J.; Adelmann, C.; Schenk, T.; Schroeder, U.; Jurczak, M.; Pourtois, G.
Title (down) 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 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
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Author Neyts, E.C.; Khalilov, U.; Pourtois, G.; van Duin, A.C.T.
Title (down) Hyperthermal oxygen interacting with silicon surfaces : adsorption, implantation, and damage creation Type A1 Journal article
Year 2011 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C
Volume 115 Issue 15 Pages 4818-4823
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Using reactive molecular dynamics simulations, we have investigated the effect of single-impact, low-energy (thermal-100 eV) bombardment of a Si(100){2 × 1} surface by atomic and molecular oxygen. Penetration probability distributions, as well as defect formation distributions, are presented as a function of the impact energy for both species. It is found that at low impact energy, defects are created chemically due to the chemisorption process in the top layers of the surface, while at high impact energy, additional defects are created by a knock-on displacement of Si. These results are of particular importance for understanding device performances of silica-based microelectronic and photovoltaic devices.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000288401200060 Publication Date 2011-03-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 28 Open Access
Notes Approved Most recent IF: 4.536; 2011 IF: 4.805
Call Number UA @ lucian @ c:irua:89858 Serial 1543
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Author Khalilov, U.; Pourtois, G.; van Duin, A.C.T.; Neyts, E.C.
Title (down) 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
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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.
Address
Corporate Author Thesis
Publisher Place of Publication Washington, D.C. Editor
Language Wos 000302924900035 Publication Date 2012-03-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 4.536 Times cited 32 Open Access
Notes Approved Most recent IF: 4.536; 2012 IF: 4.814
Call Number UA @ lucian @ c:irua:98259 Serial 1542
Permanent link to this record
 
 
Author Clima, S.; Govoreanu, B.; Jurczak, M.; Pourtois, G.
Title (down) HfOx as RRAM material : first principles insights on the working principles Type A1 Journal article
Year 2014 Publication Microelectronic engineering Abbreviated Journal Microelectron Eng
Volume 120 Issue Pages 13-18
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract First-principles simulations were employed to gain atomistic insights on the working principles of amorphous HfO2 based Resistive Random Access Memory stack: the nature of the defect responsible for the switching between the High and Low Resistive States has been unambiguously identified to be the substoichiometric Hf sites (commonly called oxygen vacancy-V-O) and the kinetics of the process have been investigated through the study of O diffusion. Also the role of each material layer in the TiN/HfO2/Hf/TiN RRAM stack and the impact of the deposition techniques have been examined: metallic Hf sputtering is needed to provide an oxygen exchange layer that plays the role of defect buffer. TiN shall be a good defect barrier for O but a bad defect buffer layer. A possible scenario to explain the device degradation (switching failure) mechanism has been proposed – the relaxation of the metastable amorphous phase towards crystalline structure leads to denser, more structured cluster that can increase the defect migration barriers. (C) 2013 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000336697300004 Publication Date 2013-08-19
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 1.806 Times cited 22 Open Access
Notes Approved Most recent IF: 1.806; 2014 IF: 1.197
Call Number UA @ lucian @ c:irua:117767 Serial 3535
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Author Vohra, A.; Khanam, A.; Slotte, J.; Makkonen, I.; Pourtois, G.; Porret, C.; Loo, R.; Vandervorst, W.
Title (down) 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 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 Mehta, A.N.; Mo, J.; Pourtois, G.; Dabral, A.; Groven, B.; Bender, H.; Favia, P.; Caymax, M.; Vandervorst, W.
Title (down) Grain-boundary-induced strain and distortion in epitaxial bilayer MoS₂ lattice Type A1 Journal article
Year 2020 Publication Journal Of Physical Chemistry C Abbreviated Journal J Phys Chem C
Volume 124 Issue 11 Pages 6472-6478
Keywords A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Grain boundaries between 60 degrees rotated and twinned crystals constitute the dominant type of extended line defects in two-dimensional transition metal dichalcogenides (2D MX2) when grown on a single crystalline template through van der Waals epitaxy. The two most common 60 degrees grain boundaries in MX2 layers, i.e., beta- and gamma-boundaries, introduce distinct distortion and strain into the 2D lattice. They impart a localized tensile or compressive strain on the subsequent layer, respectively, due to van der Waals coupling in bilayer MX2 as determined by combining atomic resolution electron microscopy, geometric phase analysis, and density functional theory. Based on these observations, an alternate route to strain engineering through controlling intrinsic van der Waals forces in homobilayer MX2 is proposed. In contrast to the commonly used external means, this approach enables the localized application of strain to tune the electronic properties of the 2D semiconducting channel in ultra-scaled nanoelectronic applications.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000526396000067 Publication Date 2020-02-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-7447; 1932-7455 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 3.7 Times cited 2 Open Access
Notes ; ; Approved Most recent IF: 3.7; 2020 IF: 4.536
Call Number UA @ admin @ c:irua:168625 Serial 6528
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Author van den Broek, B.; Houssa, M.; Iordanidou, K.; Pourtois, G.; Afanas'ev, V.V.; Stesmans, A.
Title (down) Functional silicene and stanene nanoribbons compared to graphene: electronic structure and transport Type A1 Journal article
Year 2016 Publication 2D materials Abbreviated Journal 2D Mater
Volume 3 Issue 1 Pages 015001
Keywords A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract Since the advent of graphene, other 2D materials have garnered interest; notably the single element materials silicene, germanene, and stanene. Weinvestigate the ballistic current-voltage (I-V) characteristics of armchair silicene and stanene armchair nanoribbons (AXNRs with X = Si, Sn) using a combination of density functional theory and non-equilibrium Green's functions. The impact of out-of-plane electric field and in-plane uniaxial strain on the ribbon geometries, electronic structure, and (I-V)s are considered and contrasted with graphene. Since silicene and stanene are sp(2)/sp(3) buckled layers, the electronic structure can be tuned by an electric field that breaks the sublattice symmetry, an effect absent in graphene. This decreases the current by similar to 50% for Sn, since it has the largest buckling. Uniaxial straining of the ballistic channel affects the AXNR electronic structure in multiple ways: it changes the bandgap and associated effective carrier mass, and creates a local buckling distortion at the lead-channel interface which induces a interface dipole. Due to the increasing sp(3) hybridization character with increasing element mass, large reconstructions rectify the strained systems, an effect absent in sp(2) bonded graphene. This results in a smaller strain effect on the current: a decrease of 20% for Sn at 15% tensile strain compared to a similar to 75% decrease for C.
Address
Corporate Author Thesis
Publisher IOP Publishing Place of Publication Bristol Editor
Language Wos 000373936300021 Publication Date 2016-01-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2053-1583 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 6.937 Times cited 19 Open Access
Notes Approved Most recent IF: 6.937
Call Number UA @ lucian @ c:irua:144746 Serial 4658
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Author Clima, S.; Chen, Y.Y.; Chen, C.Y.; Goux, L.; Govoreanu, B.; Degraeve, R.; Fantini, A.; Jurczak, M.; Pourtois, G.
Title (down) 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 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 Scalise, E.; Houssa, M.; Pourtois, G.; Afanas'ev, V.V.; Stesmans, A.
Title (down) 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 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
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