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Multiple Transfers of Single-Walled Carbon Nanotubes on Silicon Wafers
20 Mar 2009 | Contributor(s):: Alan Salvador Teran
Single-walled carbon nanotubes (SWCNTs) have many applications, including high speed transistor devices (see Figure 1). SWCNTs are grown on single-crystal quartz wafers and then transferred onto silicon wafers by a process that involves gold evaporation and thermal release tape. When they are...
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Role of Spin-Orbit Interaction and Berry's Phase in Aharonov-Bohm Oscillations
Papers | 04 Mar 2009 | Contributor(s):: Jeng-Bang (Tony) Yau
In this thesis we report the results of study on the role of spin-orbit (SO) interaction in Aharonov-Bohm (A-B) oscillations measured in (311)A GaAs two-dimensional (2D) holes, and the observed novel structures in the Fourier transform (FT) spectra of the A-B oscillations, which we interpret as...
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First Principles Non-Equilibrium Green's Function Modeling of Vacum and Oxide Barrier Tunneling
Papers | 01 Dec 2008 | Contributor(s):: Kirk H. Bevan
Vacuum and oxide barrier electron tunneling phenomena have been studied at length for several decades. Yet with electron device barrier widths now commonly measured in atomic units, complex quantum mechanical phenomena such as wavefunction coupling, surface states, and interface bonds have begun...
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Report of the Joint India-US Workshop on Scalable Nanomaterials for Enhanced Energy Transport, Conversion, and Efficiency
Papers | 30 Sep 2008 | Contributor(s):: Timothy S Fisher
A Joint Indo-US Workshop on "Scalable Nanomaterials for Enhanced Energy Transport, Conversion and Efficiency"was organized from August 19 to 21, 2008 at Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR) and the John F. Welch Technology Centre campus of General Electric in...
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Notes on Fermi-Dirac Integrals (4th Edition)
Papers | 23 Sep 2008 | Contributor(s):: raseong kim, Xufeng Wang, Mark Lundstrom
Fermi-Dirac integrals appear frequently in semiconductor problems, so an understanding of their properties is essential. The purpose of these notes is to collect in one place, some basic information about Fermi-Dirac integrals and their properties.We also present Matlab functions (in a zipped...
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Consistent Parameter Set for an Ensemble Monte Carlo Simulation of 4H-SiC
Papers | 01 Jul 2008 | Contributor(s):: Dragica Vasileska
A consistent parameter set is presented for Ensemble Monte Carlo simulation that simultaneously reproduces the experimental low-field and high-field characteristic transport parameters of 4H SiC.D. Vasileska and S. M. Goodnick, Computational Electronics, Morgan and Claypool, 2006.Freescale...
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Application of the Keldysh Formalism to Quantum Device Modeling and Analysis
Papers | 14 Jan 2008 | Contributor(s):: Roger Lake
The effect of inelastic scattering on quantum electron transport through layered semi-conductor structures is studied numerically using the approach based on the non-equilibrium Green's function formalism of Keldysh, Kadanoff, and Baym. The Markov assumption is not made, and the energy coordinate...
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Electron-Phonon and Electron-Electron Interactions in Quantum Transport
Papers | 14 Jan 2008 | Contributor(s):: Gerhard Klimeck
The objective of this work is to shed light on electron transport through sub-micron semi-conductor structures, where electronic state quantization, electron-electron interactions and electron-phonon interactions are important. We concentrate here on the most developed vertical quantum device,...
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High Precision Quantum Control of Single Donor Spins in Silicon
Papers | 14 Jan 2008 | Contributor(s):: Rajib Rahman, marta prada, Gerhard Klimeck, Lloyd Hollenberg
The Stark shift of the hyperfine coupling constant is investigated for a P donor in Si far below the ionization regime in the presence of interfaces using tight-binding and band minima basis approaches and compared to the recent precision measurements. In contrast with previous effective...
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Valley splitting in strained silicon quantum wells modeled with 2 degree miscuts, step disorder, and alloy disorder
Papers | 14 Jan 2008 | Contributor(s):: Neerav Kharche, marta prada, Timothy Boykin, Gerhard Klimeck
Valley splitting (VS) in strained SiGe/Si/SiGe quantum wells grown on (001) and 2° miscut substrates is computed in a magnetic field. Calculations of flat structures significantly overestimate, while calculations of perfectly ordered structures underestimate experimentally observed VS. Step...
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Atomistic Electronic Structure Calculations of Unstrained Alloyed Systems Consisting of a Million Atoms
Papers | 14 Jan 2008 | Contributor(s):: Gerhard Klimeck, Timothy Boykin
The broadening of the conduction and valence band edges due to compositional disorder in alloyed materials of finite extent is studied using an s p3 s ∗ tight binding model. Two sources of broadening due to configuration and concentration disorder are identified. The concentrational disorder...
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Simulation of highly idealized, atomic scale MQCA logic circuits
Papers | 15 Nov 2007 | Contributor(s):: Dmitri Nikonov, George Bourianoff
Spintronics logic devices based on majority gates formed by atomic-level arrangements of spins in the crystal lattice is considered. The dynamics of switching is modeled by time-dependent solution of the density-matrix equation with relaxation. The devices are shown to satisfy requirements for...
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Quantum Ballistic Transport in Semiconductor Heterostructures
Papers | 27 Aug 2007 | Contributor(s):: Michael McLennan
The development of epitaxial growth techniques has sparked a growing interest in an entirely quantum mechanical description of carrier transport. Fabrication methods, such as molecular beam epitaxy (MBE), allow for growth of ultra-thin layers of differing material compositions. Structures can be...
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Multidimensional nanoscale device modeling: the finite element method applied to the non-equilibrium Green's function formalism
Papers | 31 Oct 2006 | Contributor(s):: POLIZZI ERIC, Supriyo Datta
This work deals with the modeling and the numerical simulation of quantum transport in multidimensional open nanoscale devices. The electron transport in the device is described using the Non-Equilibrium Green's Functions (NEGF) formalism and the variational form of the problem is solved using...
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Non Equilibrium Green's Functions for Dummies: Introduction to the One Particle NEGF equations
Papers | 30 Oct 2006 | Contributor(s):: Magnus Paulsson
Non equilibrium Green's function methods are regularly used to calculate current and charge densities in nanoscale (both molecular and semiconductor) conductors under bias. This method is mainly used for ballistic conduction but may be extended to include inelastic scattering. In this tutorial...
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Modeling Quantum Transport in Nanoscale Transistors
Papers | 30 Oct 2006 | Contributor(s):: ramesh venugopal
As critical transistor dimensions scale below the 100 nm (nanoscale) regime, quan- tum mechanical effects begin to manifest themselves and affect important device performance metrics. Therefore, simulation tools which can be applied to design nanoscale transistors in the future, require new...
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Carbon Nanotube Electronics: Modeling, Physics, and Applications
Papers | 30 Oct 2006 | Contributor(s):: Jing Guo
In recent years, significant progress in understanding the physics of carbon nanotube electronic devices and in identifying potential applications has occurred. In a nanotube, low bias transport can be nearly ballistic across distances of several hundred nanometers. Deposition of high-κ...
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A Three-Dimensional Quantum Simulation of Silicon Nanowire Transistors with the Effective-Mass Approximation
Papers | 30 Oct 2006 | Contributor(s):: Jing Wang, POLIZZI ERIC, Mark Lundstrom
The silicon nanowire transistor (SNWT) is a promising device structure for future integrated circuits, and simulations will be important for understanding its device physics and assessing its ultimate performance limits. In this work, we present a three-dimensional quantum mechanical simulation...
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Electrical Resistance: an Atomistic View
Papers | 26 Oct 2006 | Contributor(s):: Supriyo Datta
This tutorial article presents a “bottom-up” view of electrical resistance starting from something really small, like a molecule, and then discussing the issues that arise as we move to bigger conductors. Remark ably enough, no serious quantum mechanics is needed to understand electrical...
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Nanoscale MOSFETs: Physics, Simulation and Design
Papers | 26 Oct 2006 | Contributor(s):: Zhibin Ren
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...