Records |
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 |
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Corporate Author |
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Thesis |
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Publisher |
American Institute of Physics |
Place of Publication ![sorted by Place of Publication field, ascending order (up)](img/sort_asc.gif) |
New York, N.Y. |
Editor |
|
Language |
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Wos |
000378923100022 |
Publication Date |
2016-06-07 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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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 |
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Author |
Kao, K.-H.; Verhulst, A.S.; Vandenberghe, W.G.; Sorée, B.; Groeseneken, G.; De Meyer, K. |
Title |
Modeling the impact of junction angles in tunnel field-effect transistors |
Type |
A1 Journal article |
Year |
2012 |
Publication |
Solid state electronics |
Abbreviated Journal |
Solid State Electron |
Volume |
69 |
Issue |
|
Pages |
31-37 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We develop an analytical model for a tunnel field-effect transistor (TFET) with a tilted source junction angle. The tunnel current is derived by using circular tunnel paths along the electric field. The analytical model predicts that a smaller junction angle improves the TFET performance, which is supported by device simulations. An analysis is also made based on straight tunnel paths and tunnel paths corresponding to the trajectory of a classical particle. In all the aforementioned cases, the same conclusions are obtained. A TFET configuration with an encroaching polygon source junction is studied to analyze the junction angle dependence at the smallest junction angles. The improvement of the subthreshold swing (SS) with decreasing junction angle can be achieved by using thinner effective oxide thickness, smaller band gap material and longer encroaching length of the encroaching junction. A TFET with a smaller junction angle on the source side also has an innate immunity against the degradation of the fringing field from the gate electrode via a high-k spacer. A large junction angle on the drain side can suppress the unwanted ambipolar current of TFETs. (c) 2011 Elsevier Ltd. All rights reserved. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication ![sorted by Place of Publication field, ascending order (up)](img/sort_asc.gif) |
Oxford |
Editor |
|
Language |
|
Wos |
000301561600009 |
Publication Date |
2012-01-16 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0038-1101; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.58 |
Times cited |
9 |
Open Access |
|
Notes |
; We acknowledge the input on nanowire processing of Rita Rooyackers and useful discussions with Wim Magnus. 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 also supported by imec's Industrial Affiliation Program. ; |
Approved |
Most recent IF: 1.58; 2012 IF: 1.482 |
Call Number |
UA @ lucian @ c:irua:97816 |
Serial |
2145 |
Permanent link to this record |
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Author |
Carrillo-Nunez, H.; Magnus, W.; Vandenberghe, W.G.; Sorée, B.; Peeters, F.M. |
Title |
Phonon-assisted Zener tunneling in a p-n diode silicon nanowire |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Solid state electronics |
Abbreviated Journal |
Solid State Electron |
Volume |
79 |
Issue |
|
Pages |
196-200 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The Zener tunneling current flowing through a biased, abrupt p-n junction embedded in a cylindrical silicon nanowire is calculated. As the band gap becomes indirect for sufficiently thick wires, Zener tunneling and its related transitions between the valence and conduction bands are mediated by short-wavelength phonons interacting with mobile electrons. Therefore, not only the high electric field governing the electrons in the space-charge region but also the transverse acoustic (TA) and transverse optical (TO) phonons have to be incorporated in the expression for the tunneling current. The latter is also affected by carrier confinement in the radial direction and therefore we have solved the Schrodinger and Poisson equations self-consistently within the effective mass approximation for both conduction and valence band electrons. We predict that the tunneling current exhibits a pronounced dependence on the wire radius, particularly in the high-bias regime. (C) 2012 Elsevier Ltd. All rights reserved. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication ![sorted by Place of Publication field, ascending order (up)](img/sort_asc.gif) |
Oxford |
Editor |
|
Language |
|
Wos |
000313611000037 |
Publication Date |
2012-09-29 |
Series Editor |
|
Series Title |
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Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0038-1101; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.58 |
Times cited |
2 |
Open Access |
|
Notes |
; This work is supported by the Flemish Science Foundation (FWO-VI), and the Interuniversity Attraction Poles, Belgium State, Belgium Science Policy, and IMEC. One of the authors (W. 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: 1.58; 2013 IF: 1.514 |
Call Number |
UA @ lucian @ c:irua:110104 |
Serial |
2600 |
Permanent link to this record |