Density functional theory based simulations of silicon nanowire field effect transistors

2016 ◽  
Vol 119 (15) ◽  
pp. 154505 ◽  
Author(s):  
Mincheol Shin ◽  
Woo Jin Jeong ◽  
Jaehyun Lee
Keyword(s):  
Density Functional Theory ◽  
Field Effect ◽  
Density Functional ◽  
Field Effect Transistors ◽  
Silicon Nanowire ◽  
Functional Theory

Ab initio performance predictions of single-layer In–V tunnel field-effect transistors

2017 ◽  
Vol 19 (30) ◽  
pp. 20121-20126 ◽  
Author(s):  
Juan Lu ◽  
Zhi-Qiang Fan ◽  
Jian Gong ◽  
Xiang-Wei Jiang
Keyword(s):  
Density Functional Theory ◽  
Ab Initio ◽  
Field Effect ◽  
Density Functional ◽  
Field Effect Transistors ◽  
Single Layer ◽  
Functional Theory ◽  
Performance Predictions ◽  
P Type

The device performances of both n-type and p-type tunnel field-effect transistors (TFETs) made of single-layer InX (X = N, P, As, Sb) are theoretically evaluated through density functional theory (DFT) and ab initio simulations in this paper.

Enhancement of tunneling current in phosphorene tunnel field effect transistors by surface defects

2018 ◽  
Vol 20 (8) ◽  
pp. 5699-5707 ◽  
Author(s):  
Juan Lu ◽  
Zhi-Qiang Fan ◽  
Jian Gong ◽  
Jie-Zhi Chen ◽  
Huhe ManduLa ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Transport Properties ◽  
Field Effect ◽  
Density Functional ◽  
Surface Defects ◽  
Field Effect Transistors ◽  
Tunneling Current ◽  
Functional Theory ◽  
Non Equilibrium Green’S Function ◽  
Nitrogen Phosphorus

The effects of the staggered double vacancies, hydrogen (H), 3d transition metals, for example cobalt, and semiconductor covalent atoms, for example, germanium, nitrogen, phosphorus (P) and silicon adsorption on the transport properties of monolayer phosphorene were studied using density functional theory and non-equilibrium Green's function formalism.

ATOMISTIC SIMULATION OF GATE EFFECT ON NANOSCALE INTRINSIC Si FIELD-EFFECT TRANSISTORS

2009 ◽  
Vol 08 (01n02) ◽  
pp. 113-117 ◽  
Author(s):  
X. F. WANG ◽  
L. N. ZHAO ◽  
Z. H. YAO ◽  
Z. F. HOU ◽  
M. YEE ◽  
...  
Keyword(s):  
Field Effect ◽  
Density Functional ◽  
Field Effect Transistors ◽  
Functional Theory ◽  
Poisson Solver ◽  
System A ◽  
Voltage Curve ◽  
Gate Effect ◽  
Multigrid Poisson Solver ◽  
Model Device

We study the electrostatic and quantum transport properties of nanoscale double-gated Si -based field effect transistors within the framework of density functional theory combined with nonequilibrium Green's function approach. In our model device system, a Si slab is sandwiched between two insulator slabs and connected to two semi-infinite Si electrodes at its left and right ends. The effect of the double gates is taken into account by applying proper electrostatic boundary conditions and solving the Poisson equation self-consistently in the system. In the representation of localized SIESTA linear combination of atomic orbitals, the study is carried out with the help of Atomistix ToolKit (ATK) package together with an efficient multigrid Poisson solver. We find that the surface potential versus gate voltage curve shows similar characteristics as in conventional MOSFETs even for devices of 1 nm size, though the shape of the curve varies with the shrink of the system. In different working regimes of the devices, the electrostatic potential and the transmission spectrum are analyzed for an atomistic understanding of the device behavior.

scholarly journals Thiazole-induced rigidification in substituted dithieno-tetrathiafulvalene: the effect of planarisation on charge transport properties

2015 ◽  
Vol 11 ◽  
pp. 1148-1154 ◽  
Author(s):  
Rupert G D Taylor ◽  
Joseph Cameron ◽  
Iain A Wright ◽  
Neil Thomson ◽  
Olena Avramchenko ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Cyclic Voltammetry ◽  
Charge Transport ◽  
Field Effect ◽  
Density Functional ◽  
Field Effect Transistor ◽  
Stille Coupling ◽  
Functional Theory ◽  
Vis Spectroscopy ◽  
Effect Transistor

Two novel tetrathiafulvalene (TTF) containing compounds 1 and 2 have been synthesised via a four-fold Stille coupling between a tetrabromo-dithienoTTF 5 and stannylated thiophene 6 or thiazole 4. The optical and electrochemical properties of compounds 1 and 2 have been measured by UV–vis spectroscopy and cyclic voltammetry and the results compared with density functional theory (DFT) calculations to confirm the observed properties. Organic field effect transistor (OFET) devices fabricated from 1 and 2 demonstrated that the substitution of thiophene units for thiazoles was found to increase the observed charge transport, which is attributed to induced planarity through S–N interactions of adjacent thiazole nitrogen atoms and TTF sulfur atoms and better packing in the bulk.

Organic Field-Effect Transistors Based on 3’-Flouro-2,2',6,6'-Tetraphenyl-4,4'-Dipyranylidene

2019 ◽  
Vol 288 ◽  
pp. 37-43
Author(s):  
Altan Bolag ◽  
Yoshiro Yamashita
Keyword(s):  
Field Effect ◽  
Density Functional ◽  
Field Effect Transistors ◽  
Organic Field Effect Transistors ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
Visible Spectroscopy ◽  
Functional Theory ◽  
X Ray ◽  
Contact Configuration

In this work, 3’-flouro-2,2',6,6'-tetraphenyl-4,4'-dipyranylidene (3FDP) was originally synthesized and investigated with density functional theory (DFT) calculations, ultraviolet–visible spectroscopy (UV–Vis) and cyclic voltammetry (CV) in comparison with 2,2',6,6'-tetraphenyl-4,4'-dipyranylidene (DP) and 4’-flouro-2,2',6,6'-tetraphenyl-4,4'-dipyranylidene (4FDP). 3FDP-based organic field-effect transistors (OFETs) were fabricated with bottom contact configuration on bare SiO2/Si substrate, 1,1,1,3,3,3-hexamethyldisilazane (HMDS) and octadecyltrichlorosilane (OTS) treated substrate, respectively. The HMDS-treated device showed highest mobility of 4 × 10−4 cm2 V−1 s−1, on/off ratio of 4 × 103 and threshold voltage of −10 V. Finally, vacuum deposited 3FDP films morphology was investigated by X-ray diffraction (XRD) analyses and the results showed higher crystallinity of HMDS-treated 3FDP film compared to the OTS-treated film, leading to a better FET performance.

Theory of Carbon-Vacancy Diffusion at the SiO2/4H-SiC Interface

2019 ◽  
Vol 963 ◽  
pp. 204-207
Author(s):  
Hind Alsnani ◽  
J.P. Goss ◽  
Patrick R. Briddon ◽  
Mark J. Rayson ◽  
Alton B. Horsfall
Keyword(s):  
Field Effect ◽  
Density Functional ◽  
Carrier Lifetime ◽  
Field Effect Transistors ◽  
Active Regions ◽  
Vacancy Diffusion ◽  
Functional Theory ◽  
Native Defects ◽  
Carbon Vacancy ◽  
Defects And Impurities

Experimental data indicate that carbon vacancies incorporated in active regions of SiC devices are important electrical defects, responsible for device limiting effects such as carrier lifetime reduction. For field-effect transistors that include a 4H-SiC/SiO2 interface, such as at the gate, the oxidation pro- cess is understood to introduce native defects to the SiC, including injection of carbon self-interstitials and vacancies, that diffuse into the active layer and interact with other defects and impurities. It is therefore important to understand the migration behaviour of primary native defects such as VC in the vicinity of 4H-SiC/SiO2 interfaces. We report here the results of a density-functional theory investi- gation into the diffusion of the carbon vacancy in such a region. We conclude that the migration of VC is significantly hindered in the immediate vicinity of the interface, with the energy of diffusion barrier being approximately 15% greater than the corresponding diffusion in bulk 4H-SiC.

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