
2010 NCN@Purdue Summer School: Electronics from the Bottom Up
18 Jan 2011 
Electronics from the Bottom Up seeks to bring a new perspective to electronic devices – one that is designed to help realize the opportunities that nanotechnology presents.

Additional Tutorials on Selected Topics in Nanotechnology
29 Mar 2011   Contributor(s):: Gerhard Klimeck, Umesh V. Waghmare, Timothy S Fisher, N. S. Vidhyadhiraja
Select tutorials in nanotechnology, a part of the 2010 NCN@Purdue Summer School: Electronics from the Bottom Up.

Analytical and Numerical Solution of the Double Barrier Problem
28 Jun 2010   Contributor(s):: Gerhard Klimeck, Parijat Sengupta, Dragica Vasileska
Tunneling is fully quantummechanical effect that does not have classical analog. Tunneling has revolutionized surface science by its utilization in scanning tunneling microscopes. In some device applications tunneling is required for the operation of the device (Resonant tunneling diodes,...

Comparison of PCPBT Lab and Periodic Potential Lab
10 Aug 2009   Contributor(s):: Abhijeet Paul, Samarth Agarwal, Gerhard Klimeck, Junzhe Geng
This small presentation provides information about the comparison performed for quantum wells made of GaAs and InAs in two different tools. This has been done to benchmark the results from completely two different sets of tools and validate the obtained results. In this presentation we provide...

Exercise: Resonant Tunneling Diode
13 Jul 2011   Contributor(s):: Dragica Vasileska, Gerhard Klimeck
This is an exercise for resonant tunneling diode.

Nanoelectronic Modeling Lecture 12: Open 1D Systems  Transmission through Double Barrier Structures  Resonant Tunneling
27 Jan 2010   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 16: Introduction to RTDs  Realistic Doping Profiles
27 Jan 2010   Contributor(s):: Gerhard Klimeck
Realistic RTDs need extremely high doping to provide enough carriers for high current densities. However, Impurity scattering can destroy the RTD performance. The dopants are therefore typically spaced 20100nm away from the central double barrier structure.

Nanoelectronic Modeling Lecture 17: Introduction to RTDs  Relaxation Scattering in the Emitter
27 Jan 2010   Contributor(s):: Gerhard Klimeck
Realistic RTDs will have nonlinear electrostatic potential in their emitter. Typically a triangular well is formed in the emitter due to the applied bias and the emitter thus contains discrete quasi bound states.

Nanoelectronic Modeling Lecture 18: Introduction to RTDs  Quantum Charge SelfConsistency (Hartree)
27 Jan 2010   Contributor(s):: Gerhard Klimeck
In this semiclassical charge and potential model the quantum mechanical simulation is performed once and the quantum mechanical charge is in general not identical to the semiclassical charge.

Nanoelectronic Modeling Lecture 19: Introduction to RTDs  Asymmetric Structures
27 Jan 2010   Contributor(s):: Gerhard Klimeck
This lecture explores this effect in more detail by targeting an RTD that has a deliberate asymmetric structure. The collector barrier is chosen thicker than the emitter barrier. With this setup we expect that the tunneling rate into the RTD from the emitter is faster than the tunneling rate...

Nanoelectronic Modeling nanoHUB Demo 1: nanoHUB Tool Usage with RTD Simulation with NEGF
09 Mar 2010   Contributor(s):: Gerhard Klimeck
Demonstration of running tools on the nanoHUB. Demonstrated is the RTD Simulation with NEGF Tool using a simple leveldrop potential model and a more realistic device using a ThomasFermi potential model.

Nanoelectronic Modeling nanoHUB Demo 2: RTD simulation with NEGF
09 Mar 2010   Contributor(s):: Gerhard Klimeck
Demonstration of resonant tunneling diode (RTD) simulation using the RTD Simulation with NEGF Tool with a Hartree potential model showing potential profile, charge densities, currentvoltage characteristics, and resonance energies. Also demonstrated is a RTD simulation using a ThomasFermi...

Nanoelectronic Modeling: Exercises 13  Barrier Structures, RTDs, and Quantum Dots
27 Jan 2010   Contributor(s):: Gerhard Klimeck
Exercises:Barrier StructuresUses: PieceWise Constant Potential Barrier ToolResonant Tunneling DiodesUses: Resonant Tunneling Diode Simulation with NEGF • Hartree calculation • Thomas Fermi potentialQuantum DotsUses: Quantum Dot Lab • pyramidal dot

Nanoelectronic Modeling: From Quantum Mechanics and Atoms to Realistic Devices
25 Jan 2010   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...

Nanoelectronic Modeling: Multimillion Atom Simulations, Transport, and HPC Scaling to 23,000 Processors
07 Mar 2008   Contributor(s):: Gerhard Klimeck
Future field effect transistors will be on the same length scales as “esoteric” devices such as quantum dots, nanowires, ultrascaled quantum wells, and resonant tunneling diodes. In those structures the behavior of carriers and their interaction with their environment need to be fundamentally...

Nanotechnology Animation Gallery
22 Apr 2010   Contributor(s):: Saumitra Raj Mehrotra, Gerhard Klimeck
Animations and visualization are generated with various nanoHUB.org tools to enable insight into nanotechnology and nanoscience. Click on image for detailed description and larger image download. Additional animations are also available Featured nanoHUB tools: Band Structure Lab. Carrier...

PCPBT: Problem Assignment for Asymmetric Barriers
24 Jun 2009   Contributor(s):: Dragica Vasileska, Gerhard Klimeck
This example demonstrates to the students that for nonsymmetric barriers which arise due to the imperfection of the molecular beam epitaxy process there is a reduction in the transmission coefficient and therefore current.

PieceWise Constant Potential Barrier Tool MATLAB Code
19 Jun 2010   Contributor(s):: Dragica Vasileska, Gerhard Klimeck
this is the MATLAB code of the PCPBT in the effective mass approximation.

Quantum Mechanics: Landauer's Formula
08 Jul 2008   Contributor(s):: Dragica Vasileska, Gerhard Klimeck
When a metallic nanojunction between two macroscopic electrodes is connected to a battery, electrical current flows across it. The battery provides, and maintains, the charge imbalance between the electrode surfaces needed to sustain steadystate conduction in the junction. This static...

Resonant Tunneling Diode Simulation with NEGF: FirstTime User Guide
20 May 2009   Contributor(s):: Samarth Agarwal, Gerhard Klimeck
This firsttime user guide for Resonant Tunneling Diode Simulation with NEGF provides some fundamental concepts regarding RTDs along with details on how device geometry and simulation parameters influence current and charge distribution inside the device.NCN@Purdue