Electrical Engineering - Electrophysics
Nonequilibrium Processes in Modern Semiconductor Devices, Spring 2003.

 TTh 11-12:20 VKC 154

A. F. J. Levi

EE 606 Outline and Course Content (PDF form)

 

EE 606 Outline and course content

Practical sub-micron and nano-scale devices usually operate in a regime dominated by non-equilibrium effects.  However, most conventional semiconductor device courses still use equilibrium or near equilibrium concepts to describe device operation.  The purpose of this course is to introduce a more realistic approach to understanding device operation in modern sub-micron and nano-scale devices.  Much of what will be introduced relies on the concept that many important non-equilibrium effects can be described in terms of a family of elementary excitations which usually only interact weakly with each other.  The course will emphasize the actual calculation of useful parameters relevant to the design and operation of practical and research devices such as scaled transistors (single-electron and quantum wire based) and scaled lasers (micro-cavity, quantum dot, and quantum wire based).

 

This course is divided into; (i) introductory material, (ii) specific examples of non-equilibrium effects determining the performance of devices, (iii) presentation of selected research papers.  Participants should have a working knowledge of quantum mechanics and semiconductor physics on a level at least comparable to EE 539 and EE 506.

 

Books worth using for reference and background reading include "Semiconductors" by D. K. Ferry, ISBN 0-02-337130-7, “Quantum Theory of the Optical and Electronic Properties of Semiconductors” by H. Haug and S. W. Koch, ISBN 981-02-0024-2, “Semiconductor-laser fundamentals” by W. W. Chow and S. W. Koch, ISBN 3-540-64166-1, “Physics of Optoelectronic Devices” by S. L. Chuang, ISBN 0-471-10939-8.

 

Some material covered by this course does not appear in any textbook.

 

There will be no class exam.

 

Part (i):

Introduction to bandstructure:  Introduction to crystal structure.  Hydrogenic orbitals.  Covalent bonding and LCAO.  Bloch states and band structure.  The tight-binding method and the k.p method.  Survey of semiconductor properties including heterostructures and modern semiconductor devices.

Introduction to dielectric functions:  Simple dielectric functions.  Plasma frequency.  Optical susceptibility and the simple oscillator model of optical absorption.  The Kramers-Kronig relations.  Lattice dynamics and the contribution of longitudinal polar-optic phonons to the dielectric function.

Introduction to electron transport:  Doping in semiconductors and rs*.  The Boltzmann transport equation including conductivity and diffusion in the relaxation-time approximation. 

Introduction to Coulomb scattering:  Elastic scattering by non-randomly positioned ionized impurities in semiconductors.  Estimating electron mobility.  Long lived quasi-particle states.  Calculation of inelastic scattering rates for non-equilibrium electrons within the RPA.  The inter-collisional field effect.

 

Part (ii):

Inelastic electron scattering:  Influence of inelastic scattering on gain in laser diodes and non-equilibrium electron transport in NETs, HBTs, and MODFETS.  Non-equilibrium effects in quantum wire and quantum dot devices.

The semiconductor laser:  Optical cavities, laser diode rate equations for single-mode, multi-mode, and quantization of photon and electron number.  Non-equilibrium phase transition in the laser. 

The avalanche photodiode:  Non-local effects in electron multiplication at breakdown.

 

Part (iii):

Presentation of research papers:

Class discussion of selected research papers.