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ABACUS Exercise: Crystal Lattices and Miler Indices

20 Jul 2010 | 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.

ABACUS Exercise: Conductivity and Carrier Concentration

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: Carriers Distribution vs. Energy

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.

Solar Cells Operation and Modeling

19 Jul 2010 | 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...

Nanoelectronic Modeling Lecture 41: Full-Band 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 multi-scale simulation of advanced InAs-based high mobility transistors.Learning Objectives:Quantum Transport Simulator Full-Band and Atomistic III-V HEMTs Performance Analysis Good Agreement with Experiment Some Open Issues...

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 Tight-Binding Orbital Model 3D Schrödinger-Poisson Solver Device Simulation Structure Optimization (Doping, Lg, VDD) LER => Localized Band Gap States LER =>...

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 nanowiresRelationship between dispersion relationship and transmission in perfectly ordered wiresBand folding in Si nanowiresTranmisison in disordered wires – relationship to an approximate...

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 engineeringWhat happens when there is disorder?Concept of disorder in the local bandstructureConfiguration noise, concentration noise,...

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 cellWhat happens when there is disorder?Concept of a supercellBand folding in a supercellBand extraction from the concept of approximate bandstructureComparison of alloy disorder...

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...

Nanoelectronic Modeling Lecture 31a: Long-Range Strain in InGaAs Quantum Dots

04 Aug 2010 | Online Presentations | Contributor(s): Gerhard Klimeck

This presentation demonstrates the importance of long-range strain in quantum dotsNumerical analysis of the importance of the buffer around the central quantum dot - local band edges – vertical and horizontal extension of the bufferControlled overgrowth can tune the electron energies in the...

Negative Differential Resistivity Exercise

28 Jun 2010 | Teaching Materials | 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...

Crystal Viewer Lab Exercise

A central problem in the investigation of material properties involves the examination of the underlying blocks that aggregate to form macroscopic bodies. These underlying blocs own a definite arrangement that is repeated in three dimensions to give the crystal structure. We will try to explore...

Band Structure Lab Exercise

Investigations of the electron energy spectra of solids form one of the most active fields of research. Knowledge of band theory is essential for application to specific problems such as Gunn diodes, tunnel diodes, photo-detectors etc. There are several standard methods to compute the band...

Analytical and Numerical Solution of the Double Barrier Problem

Tunneling is fully quantum-mechanical 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,...

Exercise for MOSFET Lab: Device Scaling

28 Jun 2010 | Teaching Materials | Contributor(s): Dragica Vasileska, Gerhard Klimeck

This exercise explores device scaling and how well devices are designed.

Piece-Wise Constant Potential Barrier Tool MATLAB Code

19 Jun 2010 | Downloads | Contributor(s): Dragica Vasileska, Gerhard Klimeck

this is the MATLAB code of the PCPBT in the effective mass approximation.

Periodic Potentials Exercise

16 Jun 2010 | Teaching Materials | Contributor(s): Gerhard Klimeck, Parijat Sengupta, Dragica Vasileska

In this exercise, various calculations of the electronic band structure of a one-dimensional crystal are performed with the Kronig-Penney (KP) model. This model has an analytical solution and therefore allows for simple calculations. More realistic models always require extensive numeric...

Quantum Tunneling Exercise

Exercise BackgroundTunneling is fully quantum-mechanical 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...

Quantum Bound States Exercise

Exercise BackgroundQuantum-mechanical systems (structures, devices) can be separated into open systems and closed systems. Open systems are characterized with propagating or current carrying states. Closed (or bound) systems are described with localized wave-functions. One such system is a...

Crystal Viewer Tool Verification (V 2.3.4)

15 Jun 2010 | Teaching Materials | Contributor(s): Dragica Vasileska, Gerhard Klimeck

This text verifies the Crystal Viewer Tool by comparing the amount of dangling bonds at the silicon surface for [100], [110] and [111] crystal orientation. The crystal viewer results are in agreement with experimental findings.

Crystal Structures - Packing Efficiency Exercise

Consider the most efficient way of packing together equal-sized spheres and stacking close-packed atomic planes in three dimensions. For example, if plane A lies beneath plane B, there are two possible ways of placing an additional atom on top of layer B. If an additional layer was placed...

Solve a Challenge for a PN Diode

08 Jun 2010 | Teaching Materials | Contributor(s): Dragica Vasileska, Gerhard Klimeck

This is SOLVE A CHALLENGE PROBLEM for pn-diodes.

Verification of the Validity of the PN Junction Tool

These simulations and comparisons with the depletion charge approximation prove the validity of the PN Junction tool.

Crystal Directions and Miller Indices

08 Jun 2010 | Teaching Materials | Contributor(s): David K. Ferry, Dragica Vasileska, Gerhard Klimeck

Miller indices are a notation system in crystallography for planes and directions in crystal lattices. In particular, a family of lattice planes is determined by three integers, l, m, and n, the Miller indices. They are written (lmn) and denote planes orthogonal to a direction (l,m,n) in the...