Gerhard Klimeck

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Resources (376-400 of 421)

  1. Homework Exercise on Drift & Diffusion in Bulk Semiconductors

    0.0 out of 5 stars 

    30 Mar 2008 | Teaching Materials | Contributor(s): Saumitra Raj Mehrotra, Gerhard Klimeck

    The tutorial questions based on Drift Diffusion Lab v1.0 available online at Drift Diffusion Lab. Students are asked to explore the concepts of Drift, Diffusion, Quasi Fermi Levels, and response to light.NCN@Purdue

  2. Homework Exercise on Bipolar Junction Transistors

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    30 Mar 2008 | Teaching Materials | Contributor(s): Saumitra Raj Mehrotra, Muhammad A. Alam, Gerhard Klimeck

    The tutorial questions are based on the Bipolar Junction Transistor Lab v1.0 available online at Bipolar Junction Transistor Lab. Students are asked to find the emitter efficiency, the base transport factor, current gains, and the Early voltage. Also a qualitative discussion is requested.NCN@Purdue

  3. BJT Lab

    4.5 out of 5 stars 

    06 Feb 2008 | Tools | Contributor(s): Saumitra Raj Mehrotra, Abhijeet Paul, Gerhard Klimeck, Dragica Vasileska, Gloria Wahyu Budiman

    This tool simulates a Bipolar Junction Transistor (BJT) using a 2D mesh. Powered by PADRE.

  4. Nanoelectronic Modeling: Multimillion Atom Simulations, Transport, and HPC Scaling to 23,000 Processors

    5.0 out of 5 stars 

    07 Mar 2008 | Online Presentations | Contributor(s): Gerhard Klimeck

    Future field effect transistors will be on the same length scales as “esoteric” devices such as quantum dots, nanowires, ultra-scaled quantum wells, and resonant tunneling diodes. In those structures the behavior of carriers and their interaction with their environment need to be fundamentally explained at a quantum mechanical level. Modeling efforts that are targeted to enhance the theoretical understanding of these devices are underway worldwide. Most of these device level descriptions utilize an effective mass approach which ignores any details of the atomic granularity. However, the concepts of device and material meet at the nanometer scale. The new device is really a new material and vice versa. A representation of the constituent materials at the atomic resolution is needed to quantitatively model devices with a countable number of atoms. While atomistic representations are novel to device physicists, the concept of finite devices that are not infinitely periodic is novel in the semiconductor materials modeling community. This presentation will provide a perspective of the NEMO 1-D and NEMO 3-D tool developments, their scaling on advanced computational resources up to 23,000 processors, their impact on the understanding of nanoelectronic devices, and the need for continued algorithm work.

  5. Drift-Diffusion Lab

    3.5 out of 5 stars 

    22 Jan 2008 | Tools | Contributor(s): Saumitra Raj Mehrotra, Abhijeet Paul, Gerhard Klimeck, Gloria Wahyu Budiman

    Simulate single semiconductor characteristics

  6. Semiconductor Device Education Material

    5.0 out of 5 stars 

    28 Jan 2008 | Teaching Materials | Contributor(s): Gerhard Klimeck

    This page has moved to "a Wiki page format" When we hear the words, semiconductor device, we may think first of the transistors in PCs or video game consoles, but transistors are the basic component in all of the electronic devices we use in our daily lives. Electronic systems are built from components such as transistors, capacitors, wires and other electronic devices such as light emitting diodes and semiconductor lasers. These components are typically integrated into a single chip made ...

  7. Periodic Potential Lab

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    19 Jan 2008 | Tools | Contributor(s): Abhijeet Paul, Junzhe Geng, Gerhard Klimeck

    Solve the time independent schrodinger eqn. for arbitrary periodic potentials

  8. Homework Exercise on Fermi-Dirac and Maxwell-Boltzmann Distributions

    0.0 out of 5 stars 

    24 Jan 2008 | Teaching Materials | Contributor(s): Abhijeet Paul, Saumitra Raj Mehrotra, Gerhard Klimeck

    The tutorial questions based on Carrier Statistics Lab v1.0 available online at Carrier Statistics Lab. Students are asked to explore the differences between Fermi-Dirac and Maxwell-Boltzmann distributions, compute electron and hole concentrations, study temperature dependences, and study freeze-out.NCN@Purdue

  9. Carrier Statistics Lab

    5.0 out of 5 stars 

    08 Jan 2008 | Tools | Contributor(s): Saumitra Raj Mehrotra, Abhijeet Paul, Gerhard Klimeck

    Calculate the electron & hole density in semiconductors

  10. Electron-Phonon and Electron-Electron Interactions in Quantum Transport

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    14 Jan 2008 | Papers | 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, the double barrier resonant tunneling diode. In this work we analyze particle interactions in two structural limits: 1) large, and 2) small cross-sections, in which the treatments are fundamentally ...

  11. High Precision Quantum Control of Single Donor Spins in Silicon

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    14 Jan 2008 | Papers | 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 mass-based results, the quadratic Stark coefficient obtained from both theories agrees closely with the experiments. It is also shown that there is a significant linear Stark effect for an impurity near the ...

  12. Valley splitting in strained silicon quantum wells modeled with 2 degree miscuts, step disorder, and alloy disorder

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    14 Jan 2008 | Papers | 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 disorder and confinement alloy disorder raise the VS to the experimentally observed levels. Atomistic alloy disorder is identified as the critical physics, which cannot be modeled with analytical effective ...

  13. Atomistic Simulation of Realistically Sized Nanodevices Using NEMO 3-D—Part II: Applications

    5.0 out of 5 stars 

    14 Jan 2008 | Papers | Contributor(s): Gerhard Klimeck, Shaikh S. Ahmed, Neerav Kharche, Marek Korkusinski, Muhammad Usman, marta prada, Timothy Boykin

    In part I, the development and deployment of a general nanoelectronic modeling tool (NEMO 3-D) has been discussed. Based on the atomistic valence-force field and the sp3d5s* nearest neighbor tight-binding models, NEMO 3-D enables the computation of strain and electronic structure in nanostructures consisting of more than 64 and 52 million atoms, corresponding to volumes of (110 nm)3 and (101 nm)3, respectively. In this part, successful applications of NEMO 3-D are demonstrated in the atomistic ...

  14. Atomistic Simulation of Realistically Sized Nanodevices Using NEMO 3-D: Part I − Models and Benchmarks

    5.0 out of 5 stars 

    14 Jan 2008 | Papers | Contributor(s): Gerhard Klimeck, Shaikh S. Ahmed, Neerav Kharche, Hansang Bae, Steven Clark, Benjamin P Haley, Maxim Naumov, Hoon Ryu, Faisal Saied, marta prada, Marek Korkusinski, Timothy Boykin

    Device physics and material science meet at the atomic scale of novel nanostructured semiconductors, and the distinction between new device or new material is blurred. Not only the quantum-mechanical effects in the electronic states of the device but also the granular atomistic representation of the underlying material are important. Approaches based on a continuum representation of the underlying material typically used by device engineers and physicists become invalid. Ab initio methods used ...

  15. Atomistic Electronic Structure Calculations of Unstrained Alloyed Systems Consisting of a Million Atoms

    0.0 out of 5 stars 

    14 Jan 2008 | Papers | 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 dominates for systems up to at least one million atoms and depends on problem size through an inverse square root law. Significant differences (over 12 meV) in band edge energies are seen depending on ...

  16. Development of a Nanoelectronic 3-D (NEMO 3-D ) Simulator for Multimillion Atom Simulations and Its Application to Alloyed Quantum Dots

    0.0 out of 5 stars 

    14 Jan 2008 | Papers | Contributor(s): Gerhard Klimeck, Timothy Boykin

    Material layers with a thickness of a few nanometers are common-place in today’s semiconductor devices. Before long, device fabrication methods will reach a point at which the other two device dimensions are scaled down to few tens of nanometers. The total atom count in such deca-nano devices is reduced to a few million. Only a small finite number of “free” electrons will operate such nano-scale devices due to quantized electron energies and electron charge. This work demonstrates that ...

  17. Crystal Viewer Tool

    4.0 out of 5 stars 

    22 Dec 2007 | Tools | Contributor(s): Yuanchen Chu, Fan Chen, Daniel F Mejia, James Fonseca, Michael Povolotskyi, Gerhard Klimeck

    Visualize different crystal lattices and planes

  18. NanoElectronic MOdeling: NEMO

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    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 quantum wells are expected to significantly enhance existing nanoelectronic technologies. The behavior of carriers and their interaction with their environment need to be fundamentally explained at a ...

  19. Engineering at the nanometer scale: Is it a new material or a new device?

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    06 Nov 2007 | Online Presentations | Contributor(s): Gerhard Klimeck

    This seminar will overview NEMO 3D simulation capabilities and its deployment on the nanoHUB as well as an overview of the nanoHUB impact on the community.

  20. Illinois 2007 Nano-Bio Workshop with nanoHUB Summer School and User Forum

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    27 Apr 2007 | Workshops | Contributor(s): Narayan Aluru, Eric Jakobsson, Umberto Ravaioli, Dave Mattson, Gerhard Klimeck, Michael McLennan

    This summer, on the campus of the University of Illinois, the NCDBN and NCN@UIUC will hold a scientific meeting on "Experimental and Computational Approaches to Understanding Membrane Assemblies and Permeation," a nanoHUB user forum, and a summer school on "Multiscale Theory, Simulation, and Reality at the Nano-Bio Interface" and the nanoHUB. Together, these will create a two-week community for learning, sharing, and doing multiscale simulation with emphasis on applications in biology.

  21. Atomistic Alloy Disorder in Nanostructures

    4.5 out of 5 stars 

    26 Feb 2007 | Online Presentations | Contributor(s): Gerhard Klimeck

    Electronic structure and quantum transport simulations are typically performed in perfectly ordered semiconductor structures. Bands and modes are defined resulting in quantized conduction and discrete states. But what if the material is fundamentally disordered? What if the disorder is at the same length scale as the device itself? This presentation will provide an introduction to the intriguing physics of disordered systems in bulk, quantum dots, nanowires, and quantum wells. The general ...

  22. CNTFET Lab

    3.0 out of 5 stars 

    13 Mar 2006 | Tools | Contributor(s): Neophytos Neophytou, Shaikh S. Ahmed, Eric Polizzi, Gerhard Klimeck, Mark Lundstrom

    Simulates ballistic transport properties in 3D Carbon NanoTube Field Effect Transistor (CNTFET) devices

  23. NanoFET

    0.0 out of 5 stars 

    13 Mar 2006 | Tools | Contributor(s): M. P. Anantram, Shaikh S. Ahmed, Alexei Svizhenko, Derrick Kearney, Gerhard Klimeck

    Simulates ballistic transport in 2D MOSFET devices

  24. CNTbands

    4.5 out of 5 stars 

    14 Dec 2006 | Tools | Contributor(s): Gyungseon Seol, Youngki Yoon, James K Fodor, Jing Guo, Akira Matsudaira, Diego Kienle, Gengchiau Liang, Gerhard Klimeck, Mark Lundstrom, Ahmed Ibrahim Saeed

    This tool simulates E-k and DOS of CNTs and graphene nanoribbons.

  25. demons

    5.0 out of 5 stars 

    31 Oct 2006 | Tools | Contributor(s): M. E. Klausmeier-Brown, C. M. Maziar, P. E. Dodd, M. A. Stettler, Xufeng Wang, Gerhard Klimeck

    Improved program consists of DEMON and SDEMON