Date of Award

2013

Document Type

Thesis

First Advisor

Iyer, Shanthi

Abstract

A superlattice (SL) is a periodic structure of layers of two (or more) materials. They are typically only a few nanometers thick (individual layers), and were discovered in the early 20th century. There are three different types of division for the miniband structures of the SL, type I, type II and type III. Type I heterostructure SL is a heterostructure where the bottom of the conduction band and the top of the valence band are formed in the same semiconductor layer. In type II, the conduction and valence band are staggered in both real and reciprocal space, so that electrons and holes are confined in different spaces. These particular devices are to be used in infrared devices and have been known to be designed in focal plane arrays and other designs for this use. The particular assignment was to find the band gap using simulation through Optel ZB 2011 software that would provide an initial guess on the SL design parameters before the growth was carried out. There were major problems that had to be addressed while simulating certain factors that we looked for in our tested quantum well (QW) and SL systems in GaAs/GaAlAs, InAs/GaInSb, InAs/GaSb and InAsN/GaInSb. Finally a comparison of the simulated and experimental data indicates that the lack of room temperature simulation as well as the inability to incorporate interfacial layers of sub monolayer thicknesses are some of the major limitations of this software.

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