
Equipment, Techniques, and Growth of UltraHigh Purity AlGaAsGaAs Heterostructures by Molecular Beam Epitaxy
26 May 2017   Contributor(s):: Geoff Gardner
In this talk I detail research and investigation into critical equipment and materials engineering issues related to the quality of the fabricated 2DEG systems. I also will present data that demonstrates the critical role gallium purity plays in 2DEG mobility.

Epitaxial Strategies for High Power Optically Pumped Vertical External Cavity Surface Emitting Lasers and Metamorphic Antimonide Solar Cells
05 Dec 2016   Contributor(s):: Ganesh Balakrishnan
We present antimonidebased photovoltaic cells grown on GaAs and Silicon substrates for use as subcells in metamorphic multijunction solar cells. These antimonide cells, based on GaSb, are designed to absorb nearinfrared photons. The GaSb layer is grown on either GaAs or Silicon substrates.

nanoHUB Simulation Activity  Orientations of Common Single Crystal Substrates
07 Jun 2016   Contributor(s):: Tanya Faltens
NEW Version 2! (10/17/16) Now includes a link to the saved set of simulations, that can be shared instantly with any nanoHUB user. Other minor edits to update the activity and fix errors. In this activity, you will use Crystal Viewer to create crystal structures with surfaces that are...

ab initio Model for Mobility and Seebeck coefficient using Boltzmann Transport (aMoBT) equation
11 Jun 2015   Contributor(s):: Alireza Faghaninia, Joel Ager (editor), Cynthia S Lo (editor)
ab initio electronic transport model to calculate lowfield electrical mobility and Seebeck coefficient of semiconductors in Boltzmann transport framework.

Exploring New Channel Materials for Nanoscale CMOS
28 Jun 2013   Contributor(s):: Anisur Rahman
The improved transport properties of new channel materials, such as Ge and IIIV semiconductors, along with new device designs, such as dual gate, tri gate or FinFETs, are expected to enhance the performance of nanoscale CMOS devices. Novel process techniques, such as ALD, high# dielectrics,...

Exit code 139
Closed  Responses: 1
GaAs with biaxial strain, swept from 3% to +3% produces the following error:
Problem launching job: Program...
http://nanohub.org/answers/question/1217

Why quantum dot simulation domain must contain multimillion atoms?
11 Jan 2013   Contributor(s):: Muhammad Usman
The InGaAs quantum dots obtained from the selfassembly growth process are heavily strained. The longrange strain and piezoelectric fields significantly modifies the electronic structure of the quantum dots. This imposes a critical constraint on the minimum size of the simulation domain to...

DBR Laser Simulator
07 Sep 2012   Contributor(s):: Nikhil Sancheti, Lynford Goddard, Christopher Adam Edwards
Describes properties of a GaAs/AlGaAs DBR laser

Quantitative Modeling and Simulation of Quantum Dots
16 Jul 2010   Contributor(s):: Muhammad Usman
Quantum dots grown by selfassembly process are typically constructed by 50,000 to 5,000,000 structural atoms which confine a small, countable number of extra electrons or holes in a space that is comparable in size to the electron wavelength. Under such conditions quantum dots can be...

Quantum Dot Wave Function (Quantum Dot Lab)
02 Feb 2011   Contributor(s):: Gerhard Klimeck, David S. Ebert, Wei Qiao
Electron density of an artificial atom. The animation sequence shows various electronic states in an Indium Arsenide (InAs)/Gallium Arsenide (GaAs) selfassembled quantum dot.

SelfAssembled Quantum Dot Structure (pyramid)
01 Feb 2011   Contributor(s):: Gerhard Klimeck, Insoo Woo, Muhammad Usman, David S. Ebert
Pyramidal InAs Quantum dot. The quantum dot is 27 atomic monolayers wide at the base and 15 atomic monolayers tall.

Quantum Dot Wave Function (still image)
31 Jan 2011   Contributor(s):: Gerhard Klimeck, David S. Ebert, Wei Qiao
Electron density of an artificial atom. The image shown displays the excited electron state in an Indium Arsenide (InAs) / Gallium Arsenide (GaAs) selfassembled quantum dot.

SelfAssembled Quantum Dot Wave Structure
31 Jan 2011   Contributor(s):: Gerhard Klimeck, Insoo Woo, Muhammad Usman, David S. Ebert
A 20nm wide and 5nm high dome shaped InAs quantum dot grown on GaAs and embedded in InAlAs is visualized.

How extensively have nanoparticles been tested in the field of solar cells?
Closed  Responses: 3
I have seen research that has included silver nanoparticles placed in the wafers of Si. I’ve also seen http://nanohub.org/answers/question/685

Atomistic Modeling and Simulation Tools for Nanoelectronics and their Deployment on nanoHUB.org
16 Dec 2010   Contributor(s):: Gerhard Klimeck
At the nanometer scale the concepts of device and material meet and a new device is a new material and vice versa. While atomistic device representations are novel to device physicists, the semiconductor materials modeling community usually treats infinitely periodic structures. Two electronic...

Is there a selfconsistent schrodingerpoisson solver on nanohub?
Closed  Responses: 0
I’m new to nanohub, and I’m looking for a selfconsistent schrodingerpoisson solver that can simulate http://nanohub.org/answers/question/619

Rode's Method: Theory and Implementation
01 Jul 2010   Contributor(s):: Dragica Vasileska
This set of teaching materials provides theoretical description of the Rode's method for the low field mobility calculation that is accompanied with a MATLAB code for the low field mobility calculation for GaAs material at different temperatures and different doping concentrations. Note that the...

Negative Differential Resistivity Exercise
28 Jun 2010   Contributor(s):: Gerhard Klimeck, Parijat Sengupta, Dragica Vasileska
In certain semiconductors such as GaAs and InP the average velocity as a function of field strength displays a maximum followed by a regime of decreasing velocity. Hilsum, Ridley, and Watkins postulated that peculiarities in the band structure of semiconductors would lead to the above...

Bulk Monte Carlo: Implementation Details and Source Codes Download
01 Jun 2010   Contributor(s):: Dragica Vasileska, Stephen M. Goodnick
The Ensemble Monte Carlo technique has been used now for over 30 years as a numerical method to simulate nonequilibrium transport in semiconductor materials and devices, and has been the subject of numerous books and reviews. In application to transport problems, a random walk is generated to...

Electronic band structure
09 Apr 2010   Contributor(s):: Saumitra Raj Mehrotra, Gerhard Klimeck
In solidstate physics, the electronic band structure (or simply band structure) of a solid describes ranges of energy in which an electron is "forbidden" or "allowed". The band structure is also often called the dispersion or the E(k) relationship. It is a mathematical relationship between the...