This article presents the comparison of SingleGate SOI and Multi-Gate SOI MOSFETs. In the first part we have presented two main fundamental problems of the “ultimate” (sub-10-nm) MOSFET scaling of Single-Gate geometry: the exponential growth of power consumption and sensitivity to fabrication uncertainties. These factors have played the decisive role in for eventual transfer of the CMOS industr...

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 ...

We study the electronic lifetimes in molecular junctions using the Keldysh nonequilibrium Green function (NEGF) model. It is found that two characteristic time scales which govern the electron tunneling phenomena. One is the electronic lifetime in which electronic energy in the molecular electronic state dissipates into the right/left electrode or vibrational mode, the other is the residence ti...

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 ...

The dimensions of electronic devices are rapidly decreasing and there is a need for a new generation of modeling tools that can accurately calculate the electrical properties of devices where atomic scale details and quantum effects are important. A promising framework for such calculations is density functional theory within the non-equilibrium Green's function formalism (NEGF-DFT). In this pa...

Semiconductor nanowires are possible candidates to replace the metal-oxide-semiconductor field-effect transistors (MOSFET) since they can act both as active devices or as device connectors. In this article, the transmission coefficients of Si and GaAs nanowires with arbitrary transport directions and cross sections are simulated in the nearestneighbor sp3d5s∗ semi-empirical tight-binding method...

Carbon-based materials such as carbon nanotubes (CNTs) and Graphene nano-ribbons (GNRs) have been extensively studied in recent years due to their exceptional electronic, opto-electronic, and mechanical properties. We employed the non-equilibrium Green’s function (NEGF) formalism to analyze the electronic and optoelectronic properties of CNTand GNRbased devices numerically. The steady-state and...

Single-molecule scanning tunneling spectroscopy (STS), with dephasing due to elastic and inelastic scattering, is of some current interest. Motivated by this, we report an extended Hückel theory (EHT)-based mean-field non-equilibrium Green’s function (NEGF) transport model with electron–phonon scattering treated within the self-consistent Born approximation (SCBA). Furthermore, a procedure base...

We perform density functional theory (DFT) calculations on molecular junctions consisting of a single molecule between two Au(111) electrodes. The molecules consist of an alkane or aryl bridge connecting acceptor, donor or thiol endgroups in various combinations. The molecular geometries are optimized and wavefunctions and eigenstates of the junction calculated using the DFT method, and then th...

The intense investigations of molecular devices, as an alternative to standard electronics components, underlines the need to model the conduction mechanisms of nano-scale conductors. In addition to measurements of the elastic conductance through point-contacts, atomic-wires and molecules, recent experiments have shown inelastic tunneling currents through, for example, a hydrogen molecule attac...