This thesis discusses device physics, modeling and design issues of nanoscale transistors at the quantum level. The principle topics addressed in this report are 1) an implementation of appropriate physics and methodology in device modeling, 2) development of a new TCAD (technology computer aided design) tool for quantum level device simulation, 3) examination and assessment of new features of ...

INTRODUCTION With the shrinking dimension of electronic devices, quantum transport attracts increasing interest. The non-equilibrium Green’s function (NEGF) formalism [1] provides a very general framework for quantum transport, but it is numerically expensive when applied on atomistic tight binding representations. So far, computational burden (in memory and CPU time) limits the maximum diamete...

We present a numerical method in this paper to calculate time-dependent transport properties in mesoscopic systems. This method recursively computes the non-equilibrium Green’s functions (NEGF) in the time domain. In the simulations, we utilize a dynamically allocated data structure to compute current densities in response to input signals of any time duration and arbitrary shape. To demonstrat...

Abstract We show quantum systems with disordered Hamiltonians may exhibit order in commonly measured quantities. This counter-intuitive situation is demonstrated using a conventional tight binding model for two-dimensional nanoribbons various boundary conditions. The analysis uses the traditional non-equilibrium Green's function (NEGF) methodology electron transport. study dragon nanodevices th...

The electronic behavior of metallic carbon nanotubes under the influence of externally applied electric fields is investigated using the Non-Equilibrium Green’s function method self consistently coupled with three-dimensional (3D) electrostatics. A nearest neighbor tight binding model based on a single pz orbital for constructing the device Hamiltonian is used. The 3D Poisson equation is solved...

A quantum transport model incorporating spin scattering processes is presented using the non-equilibrium Green's function (NEGF) formalism within the self-consistent Born approximation. This model offers a unified approach by capturing the spin-flip scattering and the quantum effects simultaneously. A numerical implementation of the model is illustrated for magnetic tunnel junction devices with...

Electron transport is computed in 3nm Si nanowires subject to incoherent scattering from phonons. The electronic structure of the nanowire is represented in an atomistic sp3d5s* tight binding basis. Phonon modes are computed in an atomistic valence force field rather than a continuum deformation potential. Atomistic transport and incoherent scattering are coupled through the non-equilibrium Gre...

The superfluid properties of disordered double-layer graphene systems are investigated using the non-equilibrium Green’s function (NEGF) formalism. The complexity of such a structure makes it imperative to study the effects of lattice vacancies which will inevitably arise during fabrication. Room-temperature performance characteristics for both ideal and disordered bilayer graphene systems are ...

The electronic properties of antimonene, single-layer Sb, are attracting great attention. In this paper, spin transport in armchair antimonene nanoribbon (ASbNR) is investigated. Following the tight-binding model, we calculate both transmission probability and conductance by means non-equilibrium Green's function (NEGF) method. effects an external electric field vertical to ribbon plane explore...

Non-equilibrium Green’s function formalism (NEGF) by employing timedependent (TD) perturbation theory is used to solve the electronic equations of motion of model systems under potential biasing conditions. The time propagation is performed in the full frequency domain of the two time variables representation. We analyze transient aspects of the resulting conductance under effects of applied di...