Modeling of Vertical Tunneling Transistor based on Gr-hBN-MoSe2 Heterostructure

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Ahmadi Golsaraki, Amir Hossein | 2023

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 56522 (05)
University: Sharif University of Technology
Department: Electrical Engineering
Advisor(s): Faez, Rahim
Abstract:
In this thesis, the transmission characteristics of a vertical tunneling transistors based on graphene-hBN-MoSe2 heterostructure is studied. We first obtain the tight-binding parameters required for Hamiltonian matrix and bandstructure calculations using density functional theory results. Once we have the tight-binding parameters, Hamiltonian and coupling matrices are calculated both of size 326×326. We then proceed to calulate the density of stated for source and drain contacts using the aforementioned matrices and nonequilibrium Green’s function(NEGF) formalism. We can then calculate the quantum capacitances of source and drain and acquire source/drain potentials using a capacitive circuit model and desnity of states,self-consistently. Lastly we use NEGF formalism to calculate transmission characteristics of our transistor. The Ion/Ioff ratio is 473 and the subthreshold swing is 224 for our heterostructure. The Ion/Ioff ratio and subthreshold swing for a Gr-hbn-Gr heterstructure with a 3 layer hBN barrier are 3 and 1534 respectively which show significant improvemet in our structure
Keywords:
Green Function ; Graphene ; Tight Binding Method ; Non Equilibrium Green ; Graphene Heterostructure ; Vertical Tunneling Transistor ; Boron Nitride

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