NANOlab Center of Excellence literature database -- Query Results

	NANOlab Center of Excellence literature database Home \| Show All \| Simple Search \| Advanced Search	Login Quick Search: Field: contains: ...
	1–30 of 115 records found matching your query (RSS \| history):

Select All Deselect All

<< 1 2 3 4 >>

List View

Citations

Details

	Records
	Author	Sorée, B.; Pham, A.-T.; Sels, D.; Magnus, W.
	Title	The junctionless nanowire transistor			Type	H3 Book chapter
	Year	2011	Publication		Abbreviated Journal
	Volume		Issue		Pages	?
	Keywords	H3 Book chapter; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher	Pan Stanford	Place of Publication	S.l.	Editor
	Language		Wos		Publication Date	0000-00-00
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN	9789814364027	Additional Links	UA library record
	Impact Factor		Times cited		Open Access
	Notes				Approved	Most recent IF: NA
	Call Number	UA @ lucian @ c:irua:93074			Serial	1754
Permanent link to this record



	Author	Magnus, W.; Carrillo-Nunez, H.; Sorée, B.
	Title	Transport in nanostructures			Type	H3 Book chapter
	Year	2011	Publication		Abbreviated Journal
	Volume		Issue		Pages
	Keywords	H3 Book chapter; Condensed Matter Theory (CMT)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher	Pan Stanford	Place of Publication	S.l.	Editor
	Language		Wos		Publication Date	0000-00-00
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN	9789814364027	Additional Links	UA library record
	Impact Factor		Times cited		Open Access
	Notes				Approved	Most recent IF: NA
	Call Number	UA @ lucian @ c:irua:93075			Serial	3724
Permanent link to this record



	Author	Tiwari, S.; Vanherck, J.; Van de Put, M.L.; Vandenberghe, W.G.; Sorée, B.
	Title	Computing Curie temperature of two-dimensional ferromagnets in the presence of exchange anisotropy			Type	A1 Journal article
	Year	2021	Publication	Physical review research	Abbreviated Journal
	Volume	3	Issue	4	Pages	043024
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We compare three first-principles methods of calculating the Curie temperature in two-dimensional (2D) ferromagnetic materials (FM), modeled using the Heisenberg model, and propose a simple formula for estimating the Curie temperature with high accuracy that works for all common 2D lattice types. First, we study the effect of exchange anisotropy on the Curie temperature calculated using the Monte Carlo (MC), the Green's function, and the renormalized spin-wave (RNSW) methods. We find that the Green's function method overestimates the Curie temperature in high-anisotropy regimes compared to the MC method, whereas the RNSW method underestimates the Curie temperature compared to the MC and the Green's function methods. Next, we propose a closed-form formula for calculating the Curie temperature of 2D FMs, which provides an estimate of the Curie temperature that is greatly improved over the mean-field expression for magnetic material screening. We apply the closed-form formula to predict the Curie temperature 2D magnets screened from the C2DB database and discover several high Curie temperature FMs, with Fe2F2 and MoI2 emerging as the most promising 2D ferromagnets. Finally, by comparing to experimental results for CrI3, CrCl3, and CrBr3, we conclude that for small effective anisotropies, the Green's-function-based equations are preferable, while for larger anisotropies, MC-based results are more predictive.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000707506500001	Publication Date	2021-10-11
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor		Times cited		Open Access	OpenAccess
	Notes				Approved	Most recent IF: NA
	Call Number	UA @ admin @ c:irua:182522			Serial	6975
Permanent link to this record



	Author	Vandenberghe, W.G.; Verhulst, A.S.; Sorée, B.; Magnus, W.; Groeseneken, G.; Smets, Q.; Heyns, M.; Fischetti, M.V.
	Title	Figure of merit for and identification of sub-60 mV/decade devices			Type	A1 Journal article
	Year	2013	Publication	Applied physics letters	Abbreviated Journal	Appl Phys Lett
	Volume	102	Issue	1	Pages	013510-13514
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	A figure of merit I60 is proposed for sub-60 mV/decade devices as the highest current where the input characteristics exhibit a transition from sub- to super-60 mV/decade behavior. For sub-60 mV/decade devices to be competitive with metal-oxide-semiconductor field-effect devices, I60 has to be in the 1-10 μA/μm range. The best experimental tunnel field-effect transistors (TFETs) in the literature only have an I60 of 6×10-3 μA/μm but using theoretical simulations, we show that an I60 of up to 10 μA/μm should be attainable. It is proven that the Schottky barrier FET (SBFET) has a 60 mV/decade subthreshold swing limit while combining a SBFET and a TFET does improve performance.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000313646500132	Publication Date	2013-01-12
	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	64	Open Access
	Notes	; William G. Vandenberghe gratefully acknowledges the support of a Ph.D. stipend from IWT-Vlaanderen. The authors thank Danielle Leonelli, Lars-Ake Ragnarsson, and Krishna Bhuwalka for useful discussions. This work was supported by imec's Industrial Affiliation Program. ;			Approved	Most recent IF: 3.411; 2013 IF: 3.515
	Call Number	UA @ lucian @ c:irua:109262			Serial	1192
Permanent link to this record



	Author	Vandenberghe, W.G.; Sorée, B.; Magnus, W.; Groeseneken, G.; Fischetti, M.V.
	Title	Impact of field-induced quantum confinement in tunneling field-effect devices			Type	A1 Journal article
	Year	2011	Publication	Applied physics letters	Abbreviated Journal	Appl Phys Lett
	Volume	98	Issue	14	Pages	143503,1-143503,3
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Being the working principle of a tunnel field-effect transistor, band-to-band tunneling is given a rigorous quantum mechanical treatment to incorporate confinement effects, multiple electron and hole valleys, and interactions with phonons. The model reveals that the strong band bending near the gate dielectric, required to create short tunnel paths, results in quantization of the energy bands. Comparison with semiclassical models reveals a big shift in the onset of tunneling. The effective mass difference of the distinct valleys is found to reduce the subthreshold swing steepness.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000289297800074	Publication Date	2011-04-06
	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	76	Open Access
	Notes	; The authors acknowledge Anne Verhulst for useful discussions. William Vandenberghe gratefully acknowledges the support of a Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). This work was supported by IMEC's Industrial Affiliation Program. ;			Approved	Most recent IF: 3.411; 2011 IF: 3.844
	Call Number	UA @ lucian @ c:irua:89297			Serial	1559
Permanent link to this record



	Author	Sorée, B.; Magnus, W.; Vandenberghe, W.
	Title	Low-field mobility in ultrathin silicon nanowire junctionless transistors			Type	A1 Journal article
	Year	2011	Publication	Applied physics letters	Abbreviated Journal	Appl Phys Lett
	Volume	99	Issue	23	Pages	233509-233509,3
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We theoretically investigate the phonon, surface roughness and ionized impurity limited low-field mobility of ultrathin silicon n-type nanowire junctionless transistors in the long channel approximation with wire radii ranging from 2 to 5 nm, as function of gate voltage. We show that surface roughness scattering is negligible as long as the wire radius is not too small and ionized impurity scattering is the dominant scattering mechanism. We also show that there exists an optimal radius where the ionized impurity limited mobility exhibits a maximum.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000298006100095	Publication Date	2011-12-09
	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	20	Open Access
	Notes	; This work is supported by the EU project SQWIRE (FP7-ICT-STREP nr. 257111). William Vandenberghe gratefully acknowledges the Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). ;			Approved	Most recent IF: 3.411; 2011 IF: 3.844
	Call Number	UA @ lucian @ c:irua:92865			Serial	1850
Permanent link to this record



	Author	Vandenberghe, W.G.; Verhulst, A.S.; Kao, K.-H.; De Meyer, K.; Sorée, B.; Magnus, W.; Groeseneken, G.
	Title	A model determining optimal doping concentration and material's band gap of tunnel field-effect transistors			Type	A1 Journal article
	Year	2012	Publication	Applied physics letters	Abbreviated Journal	Appl Phys Lett
	Volume	100	Issue	19	Pages	193509-193509,4
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We develop a model for the tunnel field-effect transistor (TFET) based on the Wentzel-Kramer-Brillouin approximation which improves over existing semi-classical models employing generation rates. We hereby introduce the concept of a characteristic tunneling length in direct semiconductors. Based on the model, we show that a limited density of states results in an optimal doping concentration as well as an optimal material's band gap to obtain the highest TFET on-current at a given supply voltage. The observed optimal-doping trend is confirmed by 2-dimensional quantum-mechanical simulations for silicon and germanium. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4714544]
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000304108000098	Publication Date	2012-05-12
	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	25	Open Access
	Notes	; William Vandenberghe gratefully acknowledges the support of a Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). This work was supported by IMEC's Industrial Affiliation Program. ;			Approved	Most recent IF: 3.411; 2012 IF: 3.794
	Call Number	UA @ lucian @ c:irua:98948			Serial	2105
Permanent link to this record



	Author	O'Regan, T.P.; Hurley, P.K.; Sorée, B.; Fischetti, M.V.
	Title	Modeling the capacitance-voltage response of In_0.53Ga_0.47As metal-oxide-semiconductor structures : charge quantization and nonparabolic corrections			Type	A1 Journal article
	Year	2010	Publication	Applied Physics Letters	Abbreviated Journal	Appl Phys Lett
	Volume	96	Issue	21	Pages	213514,1-213514,3
	Keywords	A1 Journal article; Electron Microscopy for Materials Science (EMAT);
	Abstract	The capacitance-voltage (C-V) characteristic is calculated for p-type In<sub>0.53</sub>Ga<sub>0.47</sub>As metal-oxide-semiconductor (MOS) structures based on a self-consistent PoissonSchrödinger solution. For strong inversion, charge quantization leads to occupation of the satellite valleys which appears as a sharp increase in the capacitance toward the oxide capacitance. The results indicate that the charge quantization, even in the absence of interface defects (D<sub>it</sub>), is a contributing factor to the experimental observation of an almost symmetric C-V response for In<sub>0.53</sub>Ga<sub>0.47</sub>As MOS structures. In addition, nonparabolic corrections are shown to enhance the depopulation of the Γ valley, shifting the capacitance increase to lower inversion charge densities.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000278183200090	Publication Date	2010-05-28
	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	26	Open Access
	Notes				Approved	Most recent IF: 3.411; 2010 IF: 3.841
	Call Number	UA @ lucian @ c:irua:89509			Serial	2143
Permanent link to this record



	Author	Agarwal, T.; Sorée, B.; Radu, I.; Raghavan, P.; Fiori, G.; Iannaccone, G.; Thean, A.; Heyns, M.; Dehaene, W.
	Title	Comparison of short-channel effects in monolayer MoS₂ based junctionless and inversion-mode field-effect transistors			Type	A1 Journal article
	Year	2016	Publication	Applied physics letters	Abbreviated Journal	Appl Phys Lett
	Volume	108	Issue	108	Pages	023506
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Conventional junctionless (JL) multi/gate (MuG) field-effect transistors (FETs) require extremely scaled channels to deliver high on-state current with low short-channel effect related leakage. In this letter, using ultra-thin 2D materials (e.g., monolayer MoS2), we present comparison of short-channel effects in JL, and inversion-mode (IM) FETs. We show that JL FETs exhibit better sub-threshold slope (S.S.) and drain-induced-barrier-lowering (DIBL) in comparison to IM FETs due to reduced peak electric field at the junctions. But, threshold voltage (VT) roll-off with channel length downscaling is found to be significantly higher in JL FETs than IM FETs, due to higher source/drain controlled charges (dE/dx) in the channel. Further, we show that although VT roll-off in JL FETs improves by increasing the gate control, i.e., by scaling the oxide, or channel thickness, the sensitivity of threshold voltage on structural parameters is found out to be high. (C) 2016 AIP Publishing LLC.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000370258400056	Publication Date	2016-01-16
	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	13	Open Access
	Notes	; ;			Approved	Most recent IF: 3.411
	Call Number	UA @ lucian @ c:irua:132318			Serial	4152
Permanent link to this record



	Author	Verhulst, A.S.; Verreck, D.; Pourghaderi, M.A.; Van de Put, M.; Sorée, B.; Groeseneken, G.; Collaert, N.; Thean, A.V.-Y.
	Title	Can p-channel tunnel field-effect transistors perform as good as n-channel?			Type	A1 Journal article
	Year	2014	Publication	Applied physics letters	Abbreviated Journal	Appl Phys Lett
	Volume	105	Issue	4	Pages	043103
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We show that bulk semiconductor materials do not allow perfectly complementary p- and n-channel tunnel field-effect transistors (TFETs), due to the presence of a heavy-hole band. When tunneling in p-TFETs is oriented towards the gate-dielectric, field-induced quantum confinement results in a highest-energy subband which is heavy-hole like. In direct-bandgap IIIV materials, the most promising TFET materials, phonon-assisted tunneling to this subband degrades the subthreshold swing and leads to at least 10x smaller on-current than the desired ballistic on-current. This is demonstrated with quantum-mechanical predictions for p-TFETs with tunneling orthogonal to the gate, made out of InP, In0.53Ga0.47As, InAs, and a modified version of In0.53Ga0.47As with an artificially increased conduction-band density-of-states. We further show that even if the phonon-assisted current would be negligible, the build-up of a heavy-hole-based inversion layer prevents efficient ballistic tunneling, especially at low supply voltages. For p-TFET, a strongly confined n-i-p or n-p-i-p configuration is therefore recommended, as well as a tensily strained line-tunneling configuration. (C) 2014 AIP Publishing LLC.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000341152600067	Publication Date	2014-07-30
	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	8	Open Access
	Notes	; This work was supported by imec's industrial application program. D. Verreck acknowledges the support of a Ph.D. stipend from the Institute for Promotion of Innovation through Science and Technology in Flanders (IWT). ;			Approved	Most recent IF: 3.411; 2014 IF: 3.302
	Call Number	UA @ lucian @ c:irua:134433			Serial	4587
Permanent link to this record



	Author	Vanherck, J.; Bacaksiz, C.; Sorée, B.; Milošević, M.V.; Magnus, W.
	Title	2D ferromagnetism at finite temperatures under quantum scrutiny			Type	A1 Journal article
	Year	2020	Publication	Applied Physics Letters	Abbreviated Journal	Appl Phys Lett
	Volume	117	Issue	5	Pages	052401
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Recent years have seen a tremendous rise of two-dimensional (2D) magnetic materials, several of which were verified experimentally. However, most of the theoretical predictions to date rely on ab initio methods, at zero temperature and fluctuation-free, while one certainly expects detrimental quantum fluctuations at finite temperatures. Here, we present the solution of the quantum Heisenberg model for honeycomb/hexagonal lattices with anisotropic exchange interaction up to third nearest neighbors and in an applied field in arbitrary direction, which answers the question whether long-range magnetization can indeed survive in the ultrathin limit of materials, up to which temperature, and what the characteristic excitation (magnon) frequencies are, all essential to envisaged applications of magnetic 2D materials. We find that long-range magnetic order persists at finite temperature for materials with overall easy-axis anisotropy. We validate the calculations on the examples of monolayers CrI3, CrBr3, and MnSe2. Moreover, we provide an easy-to-use tool to calculate Curie temperatures of new 2D computational materials.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000559330100001	Publication Date	2020-08-03
	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	8	Open Access
	Notes	; This work was supported by the Research Foundation-Flanders (FWO) and the special research funds of the University of Antwerp (BOF-UA). ;			Approved	Most recent IF: 4; 2020 IF: 3.411
	Call Number	UA @ admin @ c:irua:171176			Serial	6445
Permanent link to this record



	Author	Duflou, R.; Ciubotaru, F.; Vaysset, A.; Heyns, M.; Sorée, B.; Radu, I.P.; Adelmann, C.
	Title	Micromagnetic simulations of magnetoelastic spin wave excitation in scaled magnetic waveguides			Type	A1 Journal article
	Year	2017	Publication	Applied physics letters	Abbreviated Journal
	Volume	111	Issue	19	Pages	192411
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We study the excitation of spin waves in scaled magnetic waveguides using the magnetoelastic effect. In uniformly magnetized systems, normal strains parallel or perpendicular to the magnetization direction do not lead to spin wave excitation since the magnetoelastic torque is zero. Using micromagnetic simulations, we show that the nonuniformity of the magnetization in submicron waveguides due to the effect of the demagnetizing field leads to the excitation of spin waves for oscillating normal strains both parallel and perpendicular to the magnetization. The excitation by biaxial normal in-plane strain was found to be much more efficient than that by uniaxial normal out-of-plane strain. For narrow waveguides with a width of 200 nm, the excitation efficiency of biaxial normal in-plane strain was comparable to that of shear strain. Published by AIP Publishing.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000414975500027	Publication Date	2017-11-10
	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		Times cited		Open Access
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:152599			Serial	8247
Permanent link to this record



	Author	Verreck, D.; Verhulst, A.S.; Sorée, B.; Collaert, N.; Mocuta, A.; Thean, A.; Groeseneken, G.
	Title	Improved source design for p-type tunnel field-effect transistors : towards truly complementary logic			Type	A1 Journal article
	Year	2014	Publication	Applied physics letters	Abbreviated Journal	Appl Phys Lett
	Volume	105	Issue	24	Pages	243506
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Complementary logic based on tunnel field-effect transistors (TFETs) would drastically reduce power consumption thanks to the TFET's potential to obtain a sub-60 mV/dec subthreshold swing (SS). However, p-type TFETs typically do not meet the performance of n-TFETs for direct bandgap III-V configurations. The p-TFET SS stays well above 60 mV/dec, due to the low density of states in the conduction band. We therefore propose a source configuration in which a highly doped region is maintained only near the tunnel junction. In the remaining part of the source, the hot carriers in the exponential tail of the Fermi-Dirac distribution are blocked by reducing the doping degeneracy, either with a source section with a lower doping concentration or with a heterostructure. We apply this concept to n-p-i-p configurations consisting of In0.53Ga0.47As and an InP-InAs heterostructure. 15-band quantum mechanical simulations predict that the configurations with our source design can obtain sub-60 mV/dec SS, with an on-current comparable to the conventional source design. (C) 2014 AIP Publishing LLC.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000346643600076	Publication Date	2014-12-17
	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	10	Open Access
	Notes	; D. Verreck acknowledges the support of a Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). This work was supported by imec's Industrial Affiliation Program. ;			Approved	Most recent IF: 3.411; 2014 IF: 3.302
	Call Number	UA @ lucian @ c:irua:122798			Serial	1568
Permanent link to this record



	Author	Bizindavyi, J.; Verhulst, A.S.; Sorée, B.; Groeseneken, G.
	Title	Signature of ballistic band-tail tunneling current in tunnel FET			Type	A1 Journal article
	Year	2020	Publication	Ieee Transactions On Electron Devices	Abbreviated Journal	Ieee T Electron Dev
	Volume	67	Issue	8	Pages	3486-3491
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	To improve the interpretation of the tunnel field-effect transistor (TFET) measurements, we theoretically identify the signatures of the ballistic band-tail (BT) tunneling (BTT) current in the transfer and output characteristics of the TFETs. In particular, we demonstrate that the temperature dependence of a BTT-dominated subthreshold swing (SS) is in agreement with the reported experimental results. We explain how the temperature dependence of the output characteristics can be used to distinguish between a current dominated by BTT and a current dominated by trap-assisted tunneling. Finally, we propose an expression that relates the energetic extension of the quasi-extended BT states in the bandgap to the onset voltage for tunneling.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000552976100072	Publication Date	2020-07-03
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0018-9383	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.1	Times cited		Open Access
	Notes	; This work was supported by imec's Industrial Affiliation Program. ;			Approved	Most recent IF: 3.1; 2020 IF: 2.605
	Call Number	UA @ admin @ c:irua:171189			Serial	6601
Permanent link to this record



	Author	Kao, K.-H.; Verhulst, A.S.; Vandenberghe, W.G.; Sorée, B.; Groeseneken, G.; De Meyer, K.
	Title	Direct and indirect band-to-band tunneling in germanium-based TFETs			Type	A1 Journal article
	Year	2012	Publication	IEEE transactions on electron devices	Abbreviated Journal	Ieee T Electron Dev
	Volume	59	Issue	2	Pages	292-301
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Germanium is a widely used material for tunnel FETs because of its small band gap and compatibility with silicon. Typically, only the indirect band gap of Ge at 0.66 eV is considered. However, direct band-to-band tunneling (BTBT) in Ge should be included in tunnel FET modeling and simulations since the energy difference between the Ge conduction band edges at the L and G valleys is only 0.14 eV at room temperature. In this paper, we theoretically calculate the parameters A and B of Kane's direct and indirect BTBT models at different tunneling directions ([100], [110], and [111]) for Si, Ge and unstrained Si1-xGex. We highlight how the direct BTBT component becomes more important as the Ge mole fraction increases. The calculation of the band-to-band generation rate in the uniform electric field limit reveals that direct tunneling always dominates over indirect tunneling in Ge. The impact of the direct transition in Ge on the performance of two realistic tunnel field-effect transistor configurations is illustrated with TCAD simulations. The influence of field-induced quantum confinement is included in the analysis based on a back-of-the-envelope calculation.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	New York, N.Y.	Editor
	Language		Wos	000299430200005	Publication Date	2011-12-07
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0018-9383;1557-9646;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.605	Times cited	212	Open Access
	Notes	; Manuscript received August 5, 2011; revised October 5, 2011 and October 28, 2011; accepted October 30, 2011. Date of publication December 7, 2011; date of current version January 25, 2012. This work was supported by the Interuniversity Microelectronics Center's (IMEC) Industrial Affiliation Program. The work of W. G. Vandenberghe was supported by a Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). The review of this paper was arranged by Editor A. Schenk. ;			Approved	Most recent IF: 2.605; 2012 IF: 2.062
	Call Number	UA @ lucian @ c:irua:97215			Serial	708
Permanent link to this record



	Author	Kao, K.-H.; Verhulst, A.S.; Vandenberghe, W.G.; Sorée, B.; Magnus, W.; Leonelli, D.; Groeseneken, G.; De Meyer, K.
	Title	Optimization of gate-on-source-only tunnel FETs with counter-doped pockets			Type	A1 Journal article
	Year	2012	Publication	IEEE transactions on electron devices	Abbreviated Journal	Ieee T Electron Dev
	Volume	59	Issue	8	Pages	2070-2077
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We investigate a promising tunnel FET configuration having a gate on the source only, which is simultaneously exhibiting a steeper subthreshold slope and a higher ON-current than the lateral tunneling configuration with a gate on the channel. Our analysis is performed based on a recently developed 2-D quantum-mechanical simulator calculating band-to-band tunneling and including quantum confinement (QC). It is shown that the two disadvantages of the structure, namely, the sensitivity to gate alignment and the physical oxide thickness, are mitigated by placing a counter-doped parallel pocket underneath the gate-source overlap. The pocket also significantly reduces the field-induced QC. The findings are illustrated with all-Si and all-Ge gate-on-source-only tunnel field-effect transistor simulations.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	New York, N.Y.	Editor
	Language		Wos	000306920200011	Publication Date	2012-06-27
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0018-9383;1557-9646;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.605	Times cited	72	Open Access
	Notes	; Manuscript received February 17, 2012; revised May 7, 2012; accepted May 11, 2012. Date of publication June 26, 2012; date of current version July 19, 2012. This work was supported by the Interuniversity Microelectronics Center's Industrial Affiliation Program. The work of W. G. Vandenberghe was supported by the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen) through a Ph.D. stipend. The review of this paper was arranged by Editor H. S. Momose. ;			Approved	Most recent IF: 2.605; 2012 IF: 2.062
	Call Number	UA @ lucian @ c:irua:100820			Serial	2487
Permanent link to this record



	Author	Pourghaderi, M.A.; Magnus, W.; Sorée, B.; Meuris, M.; de Meyer, K.; Heyns, M.
	Title	Ballistic current in metal-oxide-semiconductor field-effect transistors: the role of device topology			Type	A1 Journal article
	Year	2009	Publication	Journal of applied physics	Abbreviated Journal	J Appl Phys
	Volume	106	Issue	5	Pages	053702,1-053702,8
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	In this study we investigate the effect of device topology on the ballistic current in n-channel metal-oxide-semiconductor field-effect transistors. Comparison of the nanoscale planar and double-gate devices reveals that, down to a certain thickness of the double gate film, the ballistic current flowing in the double gate device is twice as large compared to its planar counterpart. On the other hand, further thinning of the film beyond this threshold is found to change noticeably the confinement and transport characteristics, which are strongly depending on the film material and the surface orientation. For double gate Ge and Si devices there exists a critical film thickness below which the transverse gate field is no longer effectively screened by the inversion layer electron gas and mutual inversion of the two gates is turned on. In the case of GaAs and other similar IIIV compounds, a decrease in the film thickness may drastically change the occupation of the L-valleys and therefore amend the transport properties. The simulation results show that, in both cases, the ballistic current and the transconductance are considerably enhanced.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000269850300052	Publication Date	2009-09-03
	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	2.068	Times cited	3	Open Access
	Notes				Approved	Most recent IF: 2.068; 2009 IF: 2.072
	Call Number	UA @ lucian @ c:irua:79744			Serial	214
Permanent link to this record



	Author	Vandenberghe, W.; Sorée, B.; Magnus, W.; Fischetti, M.V.
	Title	Generalized phonon-assisted Zener tunneling in indirect semiconductors with non-uniform electric fields : a rigorous approach			Type	A1 Journal article
	Year	2011	Publication	Journal of applied physics	Abbreviated Journal	J Appl Phys
	Volume	109	Issue	12	Pages	124503-124503,12
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	A general framework to calculate the Zener current in an indirect semiconductor with an externally applied potential is provided. Assuming a parabolic valence and conduction band dispersion, the semiconductor is in equilibrium in the presence of the external field as long as the electron-phonon interaction is absent. The linear response to the electron-phonon interaction results in a non-equilibrium system. The Zener tunneling current is calculated from the number of electrons making the transition from valence to conduction band per unit time. A convenient expression based on the single particle spectral functions is provided, enabling the evaluation of the Zener tunneling current under any three-dimensional potential profile. For a one-dimensional potential profile an analytical expression is obtained for the current in a bulk semiconductor, a semiconductor under uniform field, and a semiconductor under a non-uniform field using the WKB (Wentzel-Kramers-Brillouin) approximation. The obtained results agree with the Kane result in the low field limit. A numerical example for abrupt p-n diodes with different doping concentrations is given, from which it can be seen that the uniform field model is a better approximation than the WKB model, but a direct numerical treatment is required for low bias conditions.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000292331200134	Publication Date	2011-06-21
	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	2.068	Times cited	41	Open Access
	Notes	; William Vandenberghe gratefully acknowledges the support of a Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). ;			Approved	Most recent IF: 2.068; 2011 IF: 2.168
	Call Number	UA @ lucian @ c:irua:90808			Serial	1325
Permanent link to this record



	Author	Lujan, G.S.; Sorée, B.; Magnus, W.; de Meyer, K.
	Title	A method to calculate tunneling leakage currents in silicon inversion layers			Type	A1 Journal article
	Year	2006	Publication	Journal of applied physics	Abbreviated Journal	J Appl Phys
	Volume	100	Issue	3	Pages	033708,1-5
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000239764100051	Publication Date	2006-08-30
	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	2.068	Times cited	1	Open Access
	Notes				Approved	Most recent IF: 2.068; 2006 IF: 2.316
	Call Number	UA @ lucian @ c:irua:60963			Serial	2016
Permanent link to this record



	Author	Verhulst, A.; Sorée, B.; Leonelli, D.; Vandenberghe, W.G.; Groeseneken, G.
	Title	Modeling the single-gate, double-gate, and gate-all-around tunnel field-effect transistor			Type	A1 Journal article
	Year	2010	Publication	Journal Of Applied Physics	Abbreviated Journal	J Appl Phys
	Volume	107	Issue	2	Pages	024518,1-024518,8
	Keywords	A1 Journal article; Electron Microscopy for Materials Science (EMAT);
	Abstract	Tunnel field-effect transistors (TFETs) are potential successors of metal-oxide-semiconductor FETs because scaling the supply voltage below 1 V is possible due to the absence of a subthreshold-swing limit of 60 mV/decade. The modeling of the TFET performance, however, is still preliminary. We have developed models allowing a direct comparison between the single-gate, double-gate, and gate-all-around configuration at high drain voltage, when the drain-voltage dependence is negligible, and we provide improved insight in the TFET physics. The dependence of the tunnel current on device parameters is analyzed, in particular, the scaling with gate-dielectric thickness, channel thickness, and dielectric constants of gate dielectric and channel material. We show that scaling the gate-dielectric thickness improves the TFET performance more than scaling the channel thickness and that improvements are often overestimated. There is qualitative agreement between our model and our experimental data.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000274180600122	Publication Date	2010-01-28
	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	2.068	Times cited	150	Open Access
	Notes				Approved	Most recent IF: 2.068; 2010 IF: 2.079
	Call Number	UA @ lucian @ c:irua:89507			Serial	2146
Permanent link to this record



	Author	Carrillo-Nuñez, H.; Magnus, W.; Vandenberghe, W.G.; Sorée, B.; Peeters, F.M.
	Title	Phonon-assisted Zener tunneling in a cylindrical nanowire transistor			Type	A1 Journal article
	Year	2013	Publication	Journal of applied physics	Abbreviated Journal	J Appl Phys
	Volume	113	Issue	18	Pages	184507-184508
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	The tunneling current has been computed for a cylindrical nanowire tunneling field-effect transistor (TFET) with an all-round gate that covers the source region. Being the underlying mechanism, band-to-band tunneling, mediated by electron-phonon interaction, is pronouncedly affected by carrier confinement in the radial direction and, therefore, involves the self-consistent solution of the Schrodinger and Poisson equations. The latter has been accomplished by exploiting a non-linear variational principle within the framework of the modified local density approximation taking into account the nonparabolicity of both the valence band and conduction band in relatively thick wires. Moreover, while the effective-mass approximation might still provide a reasonable description of the conduction band in relatively thick wires, we have found that the nonparabolicity of the valence band needs to be included. As a major conclusion, it is observed that confinement effects in nanowire tunneling field-effect transistors have a stronger impact on the onset voltage of the tunneling current in comparison with planar TFETs. On the other hand, the value of the onset voltage is found to be overestimated when the valence band nonparabolicity is ignored. (C) 2013 AIP Publishing LLC.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000319294100093	Publication Date	2013-05-10
	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	2.068	Times cited	4	Open Access
	Notes	; This work was supported by the Flemish Science Foundation (FWO-VI), and the Interuniversity Attraction Poles, Belgium State, Belgium Science Policy, and IMEC. ;			Approved	Most recent IF: 2.068; 2013 IF: 2.185
	Call Number	UA @ lucian @ c:irua:109651			Serial	2599
Permanent link to this record



	Author	Zhang, Y.; Fischetti, M.V.; Sorée, B.; Magnus, W.; Heyns, M.; Meuris, M.
	Title	Physical modeling of strain-dependent hole mobility in Ge p-channel inversion layers			Type	A1 Journal article
	Year	2009	Publication	Journal of applied physics	Abbreviated Journal	J Appl Phys
	Volume	106	Issue	8	Pages	083704,1-083704,9
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	We present comprehensive calculations of the low-field hole mobility in Ge p-channel inversion layers with SiO2 insulator using a six-band k·p band-structure model. The cases of relaxed, biaxially, and uniaxially (both tensily and compressively) strained Ge are studied employing an efficient self-consistent methodmaking use of a nonuniform spatial mesh and of the Broyden second methodto solve the coupled envelope-wave function k·p and Poisson equations. The hole mobility is computed using the KuboGreenwood formalism accounting for nonpolar hole-phonon scattering and scattering with interfacial roughness. Different approximations to handle dielectric screening are also investigated. As our main result, we find a large enhancement (up to a factor of 10 with respect to Si) of the mobility in the case of uniaxial compressive stress similarly to the well-known case of Si. Comparison with experimental data shows overall qualitative agreement but with significant deviations due mainly to the unknown morphology of the rough Ge-insulator interface, to additional scattering with surface optical phonon from the high- insulator, to Coulomb scattering interface traps or oxide chargesignored in our calculationsand to different channel structures employed.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000271358100050	Publication Date	2009-10-20
	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	2.068	Times cited	29	Open Access
	Notes				Approved	Most recent IF: 2.068; 2009 IF: 2.072
	Call Number	UA @ lucian @ c:irua:80137			Serial	2617
Permanent link to this record



	Author	Croitoru, M.D.; Gladilin, V.N.; Fomin, V.M.; Devreese, J.T.; Magnus, W.; Schoenmaker, W.; Sorée, B.
	Title	Quantum transport in a nanosize double-gate metal-oxide-semiconductor field-effect transistor			Type	A1 Journal article
	Year	2004	Publication	Journal of applied physics	Abbreviated Journal	J Appl Phys
	Volume	96	Issue		Pages	2305-2310
	Keywords	A1 Journal article; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000223055100081	Publication Date	2004-08-02
	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	2.068	Times cited	14	Open Access
	Notes				Approved	Most recent IF: 2.068; 2004 IF: 2.255
	Call Number	UA @ lucian @ c:irua:49454			Serial	2792
Permanent link to this record



	Author	Croitoru, M.D.; Gladilin, V.N.; Fomin, V.M.; Devreese, J.T.; Magnus, W.; Schoenmaker, W.; Sorée, B.
	Title	Quantum transport in a nanosize silicon-on-insulator metal-oxide-semiconductor field effect transistor			Type	A1 Journal article
	Year	2003	Publication	Journal of applied physics	Abbreviated Journal	J Appl Phys
	Volume	93	Issue		Pages	1230-1240
	Keywords	A1 Journal article; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000180134200069	Publication Date	2003-01-03
	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	2.068	Times cited	16	Open Access
	Notes				Approved	Most recent IF: 2.068; 2003 IF: 2.171
	Call Number	UA @ lucian @ c:irua:40874			Serial	2793
Permanent link to this record



	Author	Vandenberghe, W.; Sorée, B.; Magnus, W.; Groeseneken, G.
	Title	Zener tunneling in semiconductors under nonuniform electric fields			Type	A1 Journal article
	Year	2010	Publication	Journal of applied physics	Abbreviated Journal	J Appl Phys
	Volume	107	Issue	5	Pages	054520,1-054520,7
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Recently, a renewed interest in Zener tunneling has arisen because of its increasing impact on semiconductor device performance at nanometer dimensions. In this paper we evaluate the tunnel probability under the action of a nonuniform electric field using a two-band model and arrive at significant deviations from the commonly used Kanes model, valid for weak uniform fields only. A threshold on the junction bias where Kanes model for Zener tunneling breaks down is determined. Comparison with Kanes model particularly shows that our calculation yields a higher tunnel probability for intermediate electric fields and a lower tunnel probability for high electric fields. When performing a current calculation comparing to the WKB approximation for the case of an abrupt p-n junction significant differences concerning the shape of the I-V curve are demonstrated.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000275657500136	Publication Date	2010-03-11
	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	2.068	Times cited	22	Open Access
	Notes	; William Vandenberghe gratefully acknowledges the support of a Ph. D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). These authors acknowledge the support from IMEC's Industrial Affiliation Program and the authors would like to thank Anne Verhulst for useful comments. ;			Approved	Most recent IF: 2.068; 2010 IF: 2.079
	Call Number	UA @ lucian @ c:irua:82450			Serial	3929
Permanent link to this record



	Author	Verreck, D.; Verhulst, A.S.; Van de Put, M.; Sorée, B.; Magnus, W.; Mocuta, A.; Collaert, N.; Thean, A.; Groeseneken, G.
	Title	Full-zone spectral envelope function formalism for the optimization of line and point tunnel field-effect transistors			Type	A1 Journal article
	Year	2015	Publication	Journal of applied physics	Abbreviated Journal	J Appl Phys
	Volume	118	Issue	118	Pages	134502
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Efficient quantum mechanical simulation of tunnel field-effect transistors (TFETs) is indispensable to allow for an optimal configuration identification. We therefore present a full-zone 15-band quantum mechanical solver based on the envelope function formalism and employing a spectral method to reduce computational complexity and handle spurious solutions. We demonstrate the versatility of the solver by simulating a 40 nm wide In0.53Ga0.47As lineTFET and comparing it to p-n-i-n configurations with various pocket and body thicknesses. We find that the lineTFET performance is not degraded compared to semi-classical simulations. Furthermore, we show that a suitably optimized p-n-i-n TFET can obtain similar performance to the lineTFET. (C) 2015 AIP Publishing LLC.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000362668400025	Publication Date	2015-10-01
	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	9	Open Access
	Notes	; D. Verreck acknowledges the support of a Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). This work was supported by imec's Industrial Affiliation Program. ;			Approved	Most recent IF: 2.068; 2015 IF: 2.183
	Call Number	UA @ lucian @ c:irua:128765			Serial	4183
Permanent link to this record



	Author	Van de Put, M.L.; Vandenberghe, W.G.; Sorée, B.; Magnus, W.; Fischetti, M.V.
	Title	Inter-ribbon tunneling in graphene: An atomistic Bardeen approach			Type	A1 Journal article
	Year	2016	Publication	Journal of applied physics	Abbreviated Journal	J Appl Phys
	Volume	119	Issue	119	Pages	214306
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	A weakly coupled system of two crossed graphene nanoribbons exhibits direct tunneling due to the overlap of the wavefunctions of both ribbons. We apply the Bardeen transfer Hamiltonian formalism, using atomistic band structure calculations to account for the effect of the atomic structure on the tunneling process. The strong quantum-size confinement of the nanoribbons is mirrored by the one-dimensional character of the electronic structure, resulting in properties that differ significantly from the case of inter-layer tunneling, where tunneling occurs between bulk two-dimensional graphene sheets. The current-voltage characteristics of the inter-ribbon tunneling structures exhibit resonance, as well as stepwise increases in current. Both features are caused by the energetic alignment of one-dimensional peaks in the density-of-states of the ribbons. Resonant tunneling occurs if the sign of the curvature of the coupled energy bands is equal, whereas a step-like increase in the current occurs if the signs are opposite. Changing the doping modulates the onset-voltage of the effects as well as their magnitude. Doping through electrostatic gating makes these structures promising for application towards steep slope switching devices. Using the atomistic empirical pseudopotentials based Bardeen transfer Hamiltonian method, inter-ribbon tunneling can be studied for the whole range of two-dimensional materials, such as transition metal dichalcogenides. The effects of resonance and of step-like increases in the current we observe in graphene ribbons are also expected in ribbons made from these alternative two-dimensional materials, because these effects are manifestations of the one-dimensional character of the density-of-states. Published by AIP Publishing.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000378923100022	Publication Date	2016-06-07
	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	6	Open Access
	Notes	; ;			Approved	Most recent IF: 2.068
	Call Number	UA @ lucian @ c:irua:134652			Serial	4198
Permanent link to this record



	Author	Moors, K.; Sorée, B.; Magnus, W.
	Title	Modeling surface roughness scattering in metallic nanowires			Type	A1 Journal article
	Year	2015	Publication	Journal of applied physics	Abbreviated Journal	J Appl Phys
	Volume	118	Issue	118	Pages	124307
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	Ando's model provides a rigorous quantum-mechanical framework for electron-surface roughness scattering, based on the detailed roughness structure. We apply this method to metallic nanowires and improve the model introducing surface roughness distribution functions on a finite domain with analytical expressions for the average surface roughness matrix elements. This approach is valid for any roughness size and extends beyond the commonly used Prange-Nee approximation. The resistivity scaling is obtained from the self-consistent relaxation time solution of the Boltzmann transport equation and is compared to Prange-Nee's approach and other known methods. The results show that a substantial drop in resistivity can be obtained for certain diameters by achieving a large momentum gap between Fermi level states with positive and negative momentum in the transport direction. (C) 2015 AIP Publishing LLC.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000362565800032	Publication Date	2015-09-24
	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	11	Open Access
	Notes	; ;			Approved	Most recent IF: 2.068; 2015 IF: 2.183
	Call Number	UA @ lucian @ c:irua:129425			Serial	4207
Permanent link to this record



	Author	Andrikopoulos, D.; Sorée, B.; De Boeck, J.
	Title	Skyrmion-induced bound states on the surface of three-dimensional topological insulators			Type	A1 Journal article
	Year	2016	Publication	Journal of applied physics	Abbreviated Journal	J Appl Phys
	Volume	119	Issue	119	Pages	193903
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	The interaction between the surface of a 3D topological insulator and a skyrmion/anti-skyrmion structure is studied in order to investigate the possibility of electron confinement due to the skyrmion presence. Both hedgehog (Neel) and vortex (Bloch) skyrmions are considered. For the hedgehog skyrmion, the in-plane components cannot be disregarded and their interaction with the surface state of the topological insulator (TI) has to be taken into account. A semi-classical description of the skyrmion chiral angle is obtained using the variational principle. It is shown that both the hedgehog and the vortex skyrmion can induce bound states on the surface of the TI. However, the number and the properties of these states depend strongly on the skyrmion type and the skyrmion topological number N-Sk. The probability densities of the bound electrons are also derived where it is shown that they are localized within the skyrmion region. Published by AIP Publishing.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000377718100013	Publication Date	2016-05-18
	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	8	Open Access
	Notes	; ;			Approved	Most recent IF: 2.068
	Call Number	UA @ lucian @ c:irua:134607			Serial	4244
Permanent link to this record



	Author	Mohammed, M.; Verhulst, A.S.; Verreck, D.; Van de Put, M.; Simoen, E.; Sorée, B.; Kaczer, B.; Degraeve, R.; Mocuta, A.; Collaert, N.; Thean, A.; Groeseneken, G.
	Title	Electric-field induced quantum broadening of the characteristic energy level of traps in semiconductors and oxides			Type	A1 Journal article
	Year	2016	Publication	Journal of applied physics	Abbreviated Journal	J Appl Phys
	Volume	120	Issue	120	Pages	245704
	Keywords	A1 Journal article; Condensed Matter Theory (CMT)
	Abstract	The trap-assisted tunneling (TAT) current in tunnel field-effect transistors (TFETs) is one of the crucial factors degrading the sub-60 mV/dec sub-threshold swing. To correctly predict the TAT currents, an accurate description of the trap is required. Since electric fields in TFETs typically reach beyond 10(6) V/cm, there is a need to quantify the impact of such high field on the traps. We use a quantum mechanical implementation based on the modified transfer matrix method to obtain the trap energy level. We present the qualitative impact of electric field on different trap configurations, locations, and host materials, including both semiconductors and oxides. We determine that there is an electric-field related trap level shift and level broadening. We find that these electric-field induced quantum effects can enhance the trap emission rates. Published by AIP Publishing.
	Address
	Corporate Author				Thesis
	Publisher	American Institute of Physics	Place of Publication	New York, N.Y.	Editor
	Language		Wos	000392174000028	Publication Date	2016-12-26
	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	2.068	Times cited	6	Open Access
	Notes	; This work was supported by imec's Industrial Affiliation Program. D. Verreck acknowledges the support of a PhD stipend from IWT-Vlaanderen. ;			Approved	Most recent IF: 2.068
	Call Number	UA @ lucian @ c:irua:141481			Serial	4593
Permanent link to this record