Venugopal, Ramesh. Ph.D., Purdue University, August, 2003. Modeling Quantum Transport in Nanoscale Transistors. Major Professor: Mark Lundstrom. As critical transistor dimensions scale below the 100 nm (nanoscale) regime, quantum mechanical effects begin to manifest themselves and affect important device performance metrics. Therefore, simulation tools which can be applied to design nanoscale t...

In the present work, density functional theory (DFT) combined with non-equilibrium Green’s function (NEGF) formalism is performed. The electronic properties (band structure and density of states) and transport properties (transmission spectrum and I–V characteristics) of armchair silicene nanoribbons (ASiNRs) doped with various elements, such as Al, Ga, In, Tl, P, As, Sb and Bi, are investigate...

Two-dimensional (2D) materials and their corresponding van der Waals heterostructures have drawn tremendous interest due to their extraordinary electrical and optoelectronic properties. Insulating 2D hexagonal boron nitride (h-BN) with an atomically smooth surface has been widely used as a passivation layer to improve carrier transport for other 2D materials, especially for Transition Metal Dic...

A non-equilibrium Green function formalism (NEGF) is used to study the conductance of a side-gated quantum point contact (QPC) in the presence of lateral spin-orbit coupling (LSOC). A small difference of bias voltage between the two side gates (SGs) leads to an inversion asymmetry in the LSOC between the opposite edges of the channel. In single electron modeling of transport, this triggers a sp...

During the last 20 years since the first Quantum Cascade Laser (QCL) [1] there has been substantial development. The long-wavelength limit exploiting intersubband transitions below the reststrahlenband with frequencies in the terahertz range [2] is currently an area of active research but efforts are also being made in the opposite direction towards the short-wavelength limit. As the lasing is ...

We study electronic conductance through single molecules by subjecting a molecular junction to a time dependent potential and propagating the electronic state in real time using time-dependent density functional theory (TDDFT). This is in contrast with the more common steady-state nonequilibrium Green’s function (NEGF) method. We start by examining quantum scale conductance methods in both the ...

Multiple foodborne illness outbreaks have been associated with the consumption of fresh produce. Investigations have indicated that microbial contamination throughout the farm-to-fork continuum often contributed to these outbreaks. Researchers have hypothesized that handling practices for leafy greens in restaurants may support contamination by and proliferation and amplification of pathogens t...

A data processing scheme is proposed to deconvolve the recording footprint noise in the migration image. For computational convenience, we assume a far eld approximation and shift invariance in the Greens function. Preliminary results with synthetic data show that the footprint signature can be partially suppressed by deconvolution with the migration Greens function. However, much work needs to...

Here, in this work we have designed a molecular bridge structure which can be used as a spin filter where the prototypical highly ferromagnetic m-phenylene connected bis(aminoxyl) diradical is used as a bridging fragment between two semi-infinitely widened gold (Au) electrodes along the [100] direction. A state-of-the-art non-equilibrium Green function's (NEGF) method coupled with the density f...

Graphyne, a two-dimensional carbon allotrope like graphene but containingdoubly and triply bonded carbon atoms, has been proven to possess amazing electronic properties as graphene. Although the electronic, optical, and mechanical properties of graphyne and graphyne nanoribbons (NRs) have been previously studied, their electron transport behaviors have not been understood. Here we report a comp...