
Quantum Dots
21 Jul 2005  Online Presentations  Contributor(s): Gerhard Klimeck
Quantum Dots are manmade artificial atoms that confine electrons to a small space. As such, they have atomiclike 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 in optical sensors, lasers, and advanced electronic devices for memory and logic. This seminar starts with an overview of wavelike and particlelike properties that underly the study of quantum mechanics.

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, ultrascales Si slabs, Si nanowires, and alloyed quantum dots will be demonstrated in intuitive pictures. The presentation concludes with a brief overview of the empirical tightbinding method that bridges the gap between material science, physics, and electrical engineering for the quantitative design and analysis of nanoelectronic devices.

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 these nanowires.

Why is Nanotechnology Multidisciplinary? A perspective of one EE
19 Oct 2006  Online Presentations  Contributor(s): Gerhard Klimeck
The field of nano science and nanotechnology 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 presentation is the personal perspective of an electrical engineer who works in nanoelectronics, beginning with an introductory discussion of nanoelectronics and the formations of a multidisciplinary nano research team. An explanation is given for different lengthscales as well as the trend of device sizeshrinking. Two resulting multidisciplinary largescale modeling and simulation efforts are presented: 1) the creation of the first nanoelectronic CAD tool NEMO at Texas Instruments, and 2) the creation and operation of the community simulation web site nanoHUB.org by the Network for Computational Nanotechnology (NCN).

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 states, as well as quickly view these artificial atoms have their own particular optical absorption properties. This presentation introduces the particle in the box problem in 1D and 3D, and explores the concept of occupied and empty states, allowed transitions, and optical absorption. Students are encouraged to duplicate all the simulation results shown in the presentation. Exercises and a project or homework assignment are given at the end of the presentation.

Nanoelectronic Modeling Lecture 12: Open 1D Systems  Transmission through Double Barrier Structures  Resonant Tunneling
27 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.

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 multimillion atom simulations for the June 2005 NSF site visit to the Network for Computational Nanotechnology.

Nanoelectronic Modeling Lecture 01: Overview
25 Jan 2010  Online Presentations  Contributor(s): Gerhard Klimeck
The goal of this series of lectures is to explain the critical concepts in the understanding of the stateoftheart modeling of nanoelectronic devices such as resonant tunneling diodes, quantum wells, quantum dots, nanowires, and ultrascaled transistors. Three fundamental concepts critical to the understanding of nanoelectronic devices will be explored: 1) open systems vs. closed systems, 2) nonequilibrium systems vs. closetoequilibrium systems, and 3) atomistic material representation vs. continuum matter representation.

ECE 606 Lecture 1: Introduction/Crystal Classification
30 Aug 2012  Online Presentations  Contributor(s): Gerhard Klimeck

ECE 606 Lecture 2: Quantum Mechanics
14 Sep 2012  Online Presentations  Contributor(s): Gerhard Klimeck

ECE 606 Lecture 25: Modern MOSFETs
03 Dec 2012  Online Presentations  Contributor(s): Gerhard Klimeck

NEMO 1D: The First NEGFbased 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 multidisciplinary field.
Notably, nanotechnology has already arrived in practical devices in the world of semiconductor
electronics. Wavelike properties of electrons modify the functional device behavior once ...

ECE 606 Lecture 5: Density of States
28 Sep 2012  Online Presentations  Contributor(s): Gerhard Klimeck

Nanoelectronic Modeling Lecture 21: Recursive Green Function Algorithm
07 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 quasi1D systems. It is particularly efficient in cases where the device is partitioned into reservoirs which may be characterized by a nonHermitian Hamiltonian and a central device region which is Hermitian. Until now (2009) it also appears to be the only scalable algorithm that enables the rapid computation of incoherent transport with NEGF.

Nanoelectronic Modeling Lecture 28: Introduction to Quantum Dots and Modeling Needs/Requirements
20 Jul 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 examples and Applications
 Single electronics
 Need for quantum dot modeling
 Model requirements – what are the physical effects that need to be included?
 Overview of some of the existing theories and models
 Tight binding approach

Nanoelectronic Modeling Lecture 09: Open 1D Systems  Reflection at and Transmission over 1 Step
25 Jan 2010  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 onedimensional 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 matrix approach where wavefunction amplitude and slope are matched at the interface between the two halfspaces. Of particular interest are the wave/particle injection from the lower potential energy halfspace.

Nanoelectronic Modeling Lecture 02: (NEMO) Motivation and Background
25 Jan 2010  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 nonequilibrium 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 tools.

Nanoelectronic Modeling Lecture 11: Open 1D Systems  The Transfer Matrix Method
31 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 exhibit electrostatic band bending or include a large number of basis sets.

Nanoelectronic Modeling Lecture 20: NEGF in a Quasi1D Formulation
27 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 40: Performance Limitations of Graphene Nanoribbon Tunneling FETS due to Line Edge Roughness
05 Aug 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 TightBinding Orbital Model
 3D SchrödingerPoisson Solver
 Device Simulation
 Structure Optimization (Doping, Lg, VDD)
 LER => Localized Band Gap States
 LER => Performance Deterioration
 Outlook and Challenges
 Ripples Scattering
 More Accurate Bandstructure Model
 Dissipative Scattering (ElectronPhonon)

Investigation of the Electrical Characteristics of TripleGate FinFETs and SiliconNanowire FETs
08 Aug 2006  Online Presentations  Contributor(s): Monica Taba, Gerhard Klimeck
Electrical characteristics of various Fin fieldeffect transistors (FinFETs) and siliconnanowires were analyzed and compared using a modified threedimensional selfconsistent quantummechanical simulator in order to investigate device performance. FinFETs have been proposed to fulfill the requirement of the semiconductor road map as old devices are reaching their scaling limits. It can be expected to be manufactured in a conventional CMOS process, whereas an ideal siliconnanowire, although it has better performance, is difficult to manufacture. Simulations with different fin dimensions were done and compared to the ideal nanowire FinFET to analyze their electrical characteristics. As a result, the FinFET device can be the optimal structure with characteristics comparable to the silicon nanowire.

ECE 606 Lecture 20: Heterojunction Bipolar Transistor
17 Nov 2012  Online Presentations  Contributor(s): Gerhard Klimeck

NEMO5 Overview Presentation
17 Jul 2012  Online Presentations  Contributor(s): Tillmann Christoph Kubis, Michael Povolotskyi, Jean Michel D Sellier, James Fonseca, Gerhard Klimeck
This presentation gives an overview of the current functionality of NEMO5.

Nanoelectronic Modeling Lecture 41: FullBand and Atomistic Simulation of Realistic 40nm InAs HEMT
05 Aug 2010  Online Presentations  Contributor(s): Gerhard Klimeck, Neerav Kharche, Neophytos Neophytou, Mathieu Luisier
This presentation demonstrates the OMEN capabilities to perform a multiscale simulation of advanced InAsbased high mobility transistors.
Learning Objectives:
 Quantum Transport Simulator
 FullBand and Atomistic
 IIIV HEMTs
 Performance Analysis
 Good Agreement with Experiment
 Some Open Issues
 Outlook
 Improve Models (Contact)
 Investigate Scaling of Gate Length
 Scattering?