Quantum Dots

21 Jul 2005 | Online Presentations | Contributor(s): Gerhard Klimeck

Quantum Dots are man-made artificial atoms that confine electrons to a small space. As such, they have atomic-like behavior and enable the study of quantum mechanical effects on a length scale that is around 100 times larger than the pure atomic scale. Quantum dots offer application opportunities …

Bandstructure in Nanoelectronics

01 Nov 2005 | Online Presentations | Contributor(s): Gerhard Klimeck

This presentation will highlight, for nanoelectronic device examples, how the effective mass approximation breaks down and why the quantum mechanical nature of the atomically resolved material needs to be included in the device modeling. Atomistic bandstructure effects in resonant tunneling diodes, …

Why is Nanotechnology Multidisciplinary? A perspective of one EE

19 Oct 2006 | Online Presentations | Contributor(s): Gerhard Klimeck

The field of nano science and nano-technology covers broad areas of expertise. Classical fields of Physics, Chemistry, Material Science, Electrical/Mechanical/Chemical Engineering all are involved in the "new" field. Nano research and development is therefore multidisciplinary. This …

Numerical Aspects of NEGF: The Recursive Green Function Algorithm

14 Jun 2004 | Online Presentations | Contributor(s): Gerhard Klimeck

Numerical Aspects of NEGF: The Recursive Green Function Algorithm

Introduction to Quantum Dot Lab

31 Mar 2008 | Online Presentations | Contributor(s): Sunhee Lee, Hoon Ryu, Gerhard Klimeck

The nanoHUB tool "Quantum Dot Lab" allows users to compute the quantum mechanical "particle in a box" problem for a variety of different confinement shapes, such as boxes, ellipsoids, disks, and pyramids. Users can explore, interactively, the energy spectrum and orbital shapes of new quantized …

Thermoelectric effects in semiconductor nanostructures: Role of electron and lattice properties

06 Oct 2010 | Online Presentations | Contributor(s): Abhijeet Paul, Gerhard Klimeck

This presentation covers some aspects of present development in the field of thermoelectricity and focuses particularly on the silicon nanowires as potential thermoelectric materials. The electronic and phonon dispersions are calculated and used for the calculation of thermoelectric properties in …

HPC and Visualization for multimillion atom simulations

21 Jun 2005 | Online Presentations | Contributor(s): Gerhard Klimeck

This presentation gives an overview of the HPC and visulaization efforts involving multi-million atom simulations for the June 2005 NSF site visit to the Network for Computational Nanotechnology.

Nanoelectronic Modeling Lecture 01: Overview

30 Dec 2009 | Online Presentations | Contributor(s): Gerhard Klimeck

The goal of this series of lectures is to explain the critical concepts in the understanding of the state-of-the-art modeling of nanoelectronic devices such as resonant tunneling diodes, quantum wells, quantum dots, nanowires, and ultra-scaled transistors. Three fundamental concepts critical to …

NEMO 1-D: The First NEGF-based TCAD Tool and Network for Computational Nanotechnology

28 Dec 2004 | Online Presentations | Contributor(s): Gerhard Klimeck

Nanotechnology has received a lot of public attention since U.S. President Clinton announced the U.S. National Nanotechnology Initiative. New approaches to applications in electronics, materials, medicine, biology and a variety of other areas will be developed in this new multi-disciplinary …

Investigation of the Electrical Characteristics of Triple-Gate FinFETs and Silicon-Nanowire FETs

08 Aug 2006 | Online Presentations | Contributor(s): Monica Taba, Gerhard Klimeck

Electrical characteristics of various Fin field-effect transistors (FinFETs) and silicon-nanowires were analyzed and compared using a modified three-dimensional self-consistent quantum-mechanical simulator in order to investigate device performance. FinFETs have been proposed to fulfill the …

Parallel Computing for Realistic Nanoelectronic Simulations

12 Sep 2005 | Online Presentations | Contributor(s): Gerhard Klimeck

Typical modeling and simulation efforts directed towards the understanding of electron transport at the nanometer scale utilize single workstations as computational engines. Growing understanding of the involved physics and the need to model realistically extended devices increases the complexity …

Nanoelectronic Modeling Lecture 12: Open 1D Systems - Transmission through Double Barrier Structures - Resonant Tunneling

25 Jan 2010 | Online Presentations | Contributor(s): Gerhard Klimeck, Dragica Vasileska

This presentation shows that double barrier structures can show unity transmission for energies BELOW the barrier height, resulting in resonant tunneling. The resonance can be associated with a quasi bound state, and the bound state can be related to a simple particle in a box calculation.

Nanoelectronic Modeling Lecture 28: Introduction to Quantum Dots and Modeling Needs/Requirements

02 Mar 2010 | Online Presentations | Contributor(s): Gerhard Klimeck

This presentation provides a very high level software overview of NEMO1D. Learning Objectives: This lecture provides a very high level overview of quantum dots. The main issues and questions that are addressed are: Length scale of quantum dots Definition of a quantum dot Quantum dot …

Nanoelectronic Modeling Lecture 02: (NEMO) Motivation and Background

30 Dec 2009 | Online Presentations | Contributor(s): Gerhard Klimeck, Dragica Vasileska

Fundamental device modeling on the nanometer scale must include effect of open systems, high bias, and an atomistic basis. The non-equilibrium Green Function Formalism (NEGF) can include all these components in a fundamentally sound approach and has been the basis for a few novel device simulation …

Nanoelectronic Modeling Lecture 11: Open 1D Systems - The Transfer Matrix Method

30 Dec 2009 | Online Presentations | Contributor(s): Gerhard Klimeck, Dragica Vasileska, Samarth Agarwal, Parijat Sengupta

The transfer matrix approach is analytically exact, and “arbitrary” heterostructures can apparently be handled through the discretization of potential changes. The approach appears to be quite appealing. However, the approach is inherently unstable for realistically extended devices which …

Nanoelectronic Modeling Lecture 40: Performance Limitations of Graphene Nanoribbon Tunneling FETS due to Line Edge Roughness

08 Jul 2010 | Online Presentations | Contributor(s): Gerhard Klimeck, Mathieu Luisier

This presentation the effects of line edge roughness on graphene nano ribbon (GNR) transitors.. Learning Objectives: GNR TFET Simulation pz Tight-Binding Orbital Model 3D Schrödinger-Poisson Solver Device Simulation Structure Optimization (Doping, Lg, VDD) …

Nanoelectronic Modeling Lecture 21: Recursive Green Function Algorithm

05 Feb 2010 | Online Presentations | Contributor(s): Gerhard Klimeck

The Recursive Green Function (RGF) algorithms is the primary workhorse for the numerical solution of NEGF equations in quasi-1D systems. It is particularly efficient in cases where the device is partitioned into reservoirs which may be characterized by a non-Hermitian Hamiltonian and a central …

Nanoelectronic Modeling Lecture 20: NEGF in a Quasi-1D Formulation

25 Jan 2010 | Online Presentations | Contributor(s): Gerhard Klimeck, Samarth Agarwal, Zhengping Jiang

This lecture will introduce a spatial discretization scheme of the Schrödinger equation which represents a 1D heterostructure like a resonant tunneling diode with spatially varying band edges and effective masses.

Nanoelectronic Modeling Lecture 10: Open 1D Systems - Transmission through & over 1 Barrier

30 Dec 2009 | Online Presentations | Contributor(s): Gerhard Klimeck, Dragica Vasileska, Samarth Agarwal

Tunneling and interference are critical in the understanding of quantum mechanical systems. The 1D time independent Schrödinger equation can be easily solved analytically in a scattering matrix approach for a system of a single potential barrier. The solution is obtained by matching wavefunction …

Nanoelectronic Modeling Lecture 08: Introduction to Bandstructure Engineering II

30 Dec 2009 | Online Presentations | Contributor(s): Gerhard Klimeck

This presentation provides a brief overview of the concepts of bandstructure engineering and its potential applications to light detectors, light emitters, and electron transport devices. Critical questions of the origin of bandstructure and its dependence on local atom arrangements are raised to …

Nanoelectronic Modeling Lecture 41: Full-Band and Atomistic Simulation of Realistic 40nm InAs HEMT

08 Jul 2010 | Online Presentations | Contributor(s): Gerhard Klimeck, Neerav Kharche, Neophytos Neophytou, Mathieu Luisier

This presentation demonstrates the OMEN capabilities to perform a multi-scale simulation of advanced InAs-based high mobility transistors. Learning Objectives: Quantum Transport Simulator Full-Band and Atomistic III-V HEMTs Performance Analysis Good Agreement …

Nanoelectronic Modeling Lecture 09: Open 1D Systems - Reflection at and Transmission over 1 Step

30 Dec 2009 | Online Presentations | Contributor(s): Gerhard Klimeck, Dragica Vasileska, Samarth Agarwal

One of the most elemental quantum mechanical transport problems is the solution of the time independent Schrödinger equation in a one-dimensional system where one of the two half spaces has a higher potential energy than the other. The analytical solution is readily obtained using a scattering …

NanoElectronic MOdeling: NEMO

20 Dec 2007 | Online Presentations | Contributor(s): Gerhard Klimeck

This presentation was one of 13 presentations in the one-day forum, "Excellence in Computer Simulation," which brought together a broad set of experts to reflect on the future of computational science and engineering. Novel nanoelectronic devices such as quantum dots, nanowires, and ultra-scaled …

NEMO 3D: Intel optimizations and Multiple Quantum Dot Simulations

03 Aug 2006 | Online Presentations | Contributor(s): Anish Dhanekula, Gerhard Klimeck

NEMO-3D is a nanoelectronic modeling tool that analyzes the electronic structure of nanoscopic devices. Nanoelectronic devices such as Quantum Dots (QDs) can contain millions of atoms,. Therefore, simulating their electronic structure, can take up to several days. In order to simulate and analyze …

Nanoelectronic Modeling Lecture 33: Alloy Disorder in Bulk

07 Jul 2010 | Online Presentations | Contributor(s): Gerhard Klimeck, Timothy Boykin, Chris Bowen

This presentation discusses disorder in AlGaAs unstrained systems in bulk. Bandstructure of an ideal simple unit cell What happens when there is disorder? Concept of a supercell Band folding in a supercell Band extraction from the concept of approximate …