
ABACUS: Test for Bandstructure Lab
10 Aug 2010  Teaching Materials  Contributor(s): Dragica Vasileska, Gerhard Klimeck
This is a test that examines ones understanding of electronic structure once he/she has gone through the materials and exercises provided on the nanoHUB as part of the ABACUS Bandstructure topic page and running the Bandstructure Lab.

ABACUS: Test for Carrier Statistics Tool
10 Aug 2010  Teaching Materials  Contributor(s): Saumitra Raj Mehrotra, Dragica Vasileska, Gerhard Klimeck
The objective of this test is to give an idea to a selflearning students or to instructors in the case this test is used in a classroom the level of understanding of this topic when students have gone through the learning material, worked exercises and have completed the assignments and the challenge problem.

Carrier Statistics  Temperature Effects
10 Aug 2010  Teaching Materials  Contributor(s): Saumitra Raj Mehrotra, Dragica Vasileska, Gerhard Klimeck
Silicon (Si), Germanium (Ge) and GalliumArsenide (GaAs) are commonly used materials for MOS Field Effect Transistor (MOSFET) fabrication. MOSFET structures are commonly doped to achieve the desired switching operation and doping is a critical parameter in MOSFET designing.
The goal in this test is to calculate the temperature range of device operation using Si,Ge and GaAs materials.

ABACUS: MOSFET  Diffusion Process
09 Aug 2010  Teaching Materials  Contributor(s): Dragica Vasileska, Gerhard Klimeck
The goal of this assignment is to make familiar the students the required doses in the diffusion step of fabrication of semiconductor devices to get certain values of the volume doping densities.

ABACUS: Test for PN Junction Lab
09 Aug 2010  Teaching Materials  Contributor(s): Dragica Vasileska, Gerhard Klimeck
The objective of this test is to give an idea to a selflearning students or to instructors in the case this test is used in a classroom the level of understanding of this topic when students have gone through the learning material, worked exercises and have completed the assignments and the challenge problem.

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?

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)

Nanoelectronic Modeling Lecture 35: Alloy Disorder in Nanowires
05 Aug 2010  Online Presentations  Contributor(s): Gerhard Klimeck, Timothy Boykin, Neerav Kharche, Mathieu Luisier, Neophytos Neophytou
This presentation discusses the consequences of Alloy Disorder in unstrained strained AlGaAs nanowires
 Relationship between dispersion relationship and transmission in perfectly ordered wires
 Band folding in Si nanowires
 Tranmisison in disordered wires – relationship to an approximate bandstructre
 Reminder of the origin of bandstructure and bandstructure engineering
 Localization of wavefunctions
Learning Objectives:
 Alloy wires are NOT smooth
 “Conduction band edge” flucatuates locally
 Dispersion changes
 Transmission and Density of states show localization effects

Nanoelectronic Modeling Lecture 34: Alloy Disorder in Quantum Dots
05 Aug 2010  Online Presentations  Contributor(s): Gerhard Klimeck, Timothy Boykin, Chris Bowen
This presentation discusses the consequences of Alloy Disorder in strained InGaAs Quantum Dots
 Reminder of the origin of bandstructure and bandstructure engineering
 What happens when there is disorder?
 Concept of disorder in the local bandstructure
 Configuration noise, concentration noise, clustering
Learning Objectives:
 Devicetodevice fluctuations in nanostructures may be significant even if the shape and size of the quantum dots remain perfectly controlled.
 Configuration noise, concentration noise and clustering in perfectly size and shape controlled quantum dots can lead to optical transition fluctuations that should be experimentally relevant.

ABACUS: Test for Crystal Viewer Tool
05 Aug 2010  Teaching Materials  Contributor(s): Dragica Vasileska, Gerhard Klimeck
The objective of this test is to give an idea to a selflearning students or to instructors in the case this test is used in a classroom the level of understanding of this topic when students have gone through the learning material, worked exercises and have completed the assignments and the challenge problem.

ABACUS: Test for Periodic Potential Lab
05 Aug 2010  Teaching Materials  Contributor(s): Dragica Vasileska, Gerhard Klimeck
The objective of this test is to give an idea to a selflearning students or to instructors in the case this test is used in a classroom the level of understanding of this topic when students have gone through the learning material, worked exercises and have completed the assignments and the challenge problem.

ABACUS: Test for PCPBT Lab
05 Aug 2010  Teaching Materials  Contributor(s): Dragica Vasileska, Gerhard Klimeck
The objective of this test is to give an idea to a selflearning students or to instructors in the case this test is used in a classroom the level of understanding of this topic when students have gone through the learning material, worked exercises and have completed the assignments and the challenge problem.

Nanoelectronic Modeling Lecture 33: Alloy Disorder in Bulk
04 Aug 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 bandstructure
 Comparison of alloy disorder with the virtual crystal approximation
 Configuration noise, concentration noise
 How large does an alloy supercell have to be? When does the “bulk” condition occur?
Learning Objectives:
 Bandedges and bandgaps are influenced by:
 Placement / configuration disorder
 Concentration noise
 Clustering
 System size is very important
 “bulk” starts at 100,000 atoms
 => Nanostructures are not “bulk”
=> like quantum dots, nanowires, and quantum wells vary locally

Nanoelectronic Modeling Lecture 32: Strain Layer Design through Quantum Dot TCAD
04 Aug 2010  Online Presentations  Contributor(s): Gerhard Klimeck, Muhammad Usman
This presentation demonstrates the utilization of NEMO3D to understand complex experimental data of embedded InAs quantum dots that are selectively overgrown with a strain reducing InGaAs layer. Different alloy concentrations of the strain layer tune the optical emission and absorption wavelength of the quantum dots. The role of the nonlinear strain behavior ovserved in the experimental data is explored in NEMO3D. The simulation engine serves as a virtual microscope to understand the interplay of disorder, strain, and quantum dot shape.
Learning Objectives:
 Objective:
 Optical emission at 1.5μm without GaN
 Understand experimental data on QD spectra in selective overgrowth
 Approach:
 Model large structure
 60nm x 60nm x 60nm
 9 million atoms
 No changes to the published tight binding parameters
 Result:
 Match experiment remarkably well
 Strain
 change in quantum dot aspect ratio
 Quantitative model of complex system
 Studied sensitivity to experimental imperfections – small variations
 Effective mass theories provided the wrong guidance

Nanoelectronic Modeling Lecture 31a: LongRange Strain in InGaAs Quantum Dots
04 Aug 2010  Online Presentations  Contributor(s): Gerhard Klimeck
This presentation demonstrates the importance of longrange strain in quantum dots
 Numerical analysis of the importance of the buffer around the central quantum dot  local band edges – vertical and horizontal extension of the buffer
 Controlled overgrowth can tune the electron energies in the system
Learning Objectives:
 Strain is the source of the creation of the InAs QDs on GaAs
 Strain is a long range phenomenon
 Strain reaches further vertically than horizontally
 Quantum dots will grow on top of each other
 Electron wavefunctions are confined to the central quantum dots and can be computed in a smaller domain

Nanoelectronic Modeling Lecture 29: Introduction to the NEMO3D Tool
04 Aug 2010  Online Presentations  Contributor(s): Gerhard Klimeck
This presentation provides a very high level software overview of NEMO3D. The items discussed are:
 Modeling Agenda and Motivation
 TightBinding Motivation and basic formula expressions
 Tight binding representation of strainSoftware structure
 NEMO3D algorithm flow
 NEMO3D parallelization scheme – original 1D spatial decomposition
 NEMO3D scaling on parallel computes from the year 2000 til 2007
 New 1D, 2D, and 3D spatial decomposition scheme and parallel performance
 52 million atom simulation demonstration
Learning Objectives:
 Convey a broad overview of the NEMO3D simulation engine.
 Student shall learn about the algorithmic coponents of geometry construction, atom position computaion, and electronic structure calculation.
 Student shall learn the need and usefulness of parallel computers to solve the NEMO3D problems.
 Student shall learn a demonstration of a software capability and validation.

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

AQME Exercise: Bound States – Theoretical Exercise
20 Jul 2010  Teaching Materials  Contributor(s): Dragica Vasileska, Gerhard Klimeck
The objective of this exercise is to teach the students the theory behind bound states in a quantum well.

ABACUS Exercise: Light Shining on a Semiconductor
20 Jul 2010  Teaching Materials  Contributor(s): Dragica Vasileska, Gerhard Klimeck
The objective of this exercise is to examine the behavior of semiconductors under illumination with light.

SCHRED Exercise: MOS Capacitor Analysis
20 Jul 2010  Teaching Materials  Contributor(s): Dragica Vasileska, Gerhard Klimeck
The objective of this exercise is to examine the influence of semiclassical and quantummechanical charge description on the lowfrequency CVcurves. It also teaches one the influence of polygate depletion on the lowfrequency CVcurves.

ABACUS Exercise: Bandstructure – KronigPenney Model and TightBinding Exercise
20 Jul 2010  Teaching Materials  Contributor(s): Dragica Vasileska, Gerhard Klimeck
The objective of this exercise is to start with the simple KronigPenney model and understand formations of bands and gaps in the dispersion relation that describes the motion of carriers in 1D periodic potentials. The second exercise examines the behavior of the bands at the Brillouin zone boundaries. Finally, a simplified tightbinding approach for 1D lattice has to be derived as part of the third exercise..

ABACUS Exercise: Carriers Distribution vs. Energy
20 Jul 2010  Teaching Materials  Contributor(s): Dragica Vasileska, Gerhard Klimeck
The objective of this problem is to teach the students how the occupancy function changes with temperature, therefore affecting the population of available energy states in the conduction and valence bands.

ABACUS Exercise: Conductivity and Carrier Concentration
20 Jul 2010  Teaching Materials  Contributor(s): Dragica Vasileska, Gerhard Klimeck
The objective of the first problem is to teach the students how to calculate carrier conductivity in a bulk semiconductor material. The objective of the second problem is to calculate the electron and hole concentrations in a bulk sample for fixed donor and varying acceptor concentration.

ABACUS Exercise: Crystal Lattices and Miler Indices
20 Jul 2010  Teaching Materials  Contributor(s): Dragica Vasileska, Gerhard Klimeck
The objective of these assignments is to teach the students about crystal lattices and Miler indices for planes and directions.

Solar Cells Operation and Modeling
19 Jul 2010  Teaching Materials  Contributor(s): Dragica Vasileska, Gerhard Klimeck
This set of slides decribes the basic principles of operation of various generations on solar cells with emphasis to single crystalline solar cells. Next, semiconductor equations that describe the operation of a solar cell under simplified conditions is given. Finally, modeling of single junction solar cells is described. Modeling of solar cells with Silvaco simulation software is also outlined.
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