Electronic properties and microhardness of semiconductor alloys

Show full item record

Title: Electronic properties and microhardness of semiconductor alloys
Author: Ekpenuma, Sylvester Nwabuzor
Abstract: The results of theoretical investigations of the properties of semiconductor alloys are presented . First , the effects of alloy disorder on the electronic properties of four III -V quaternary alloys are investigated using an extension of the bonding -antibonding coherent potential approximation (CPA ) formalism . The alloys considered have two disordered sublattices so that their chemical formulae have the general form AxBi _a ;CyDi _y . Some alloys of this type are used in optoelectronic devices . Results are presented for the densities of states , the self energies , and the band gap bowing for the alloys Ala .Gai _a .AsyPi _y , AliGai _xAsySbi _y , Gaa :Ini _a :AsyPi _y , and Gaa .Ini _a :AsySbi _y . Comparisons of these CPA results are made with Virtual Crystal Approximation (VGA ) results , and with experimental data where available . Second , the electronic properties of the II -VI alloy Hgi _a . _yCda .ZnyTe are calculated . To do this , an extension is made of a previously developed CPA formalism for quaternary alloys of the form Ai _a . _yBa ;CyD to include spin -orbit coupling in the input bandstructures . This study is motivated by recent results that indicate improvement in the structural properties of the widely used infrared material Hgi _a .Cda .Te on the addition of few per cent zinc . Results for the effective masses and band gap variations with compositions are presented . Lastly , a formalism for the calculation of the alloy microstructural hardness is developed . This formalism combines a solid -solution hardening model , an analysis of the composition dependence of critical stress , and an empirical relation for the alloy hardness . Results for the hardness variations with composition for the II -VI alloys Cdi _a ;Zna :Te , Hgi _a .Cda .Te , Hgi _a ;ZnxTe , and Hgi _a ; _yCda ;ZnyTe are presented and compared with available data . The results for Hgi _a : -yCda ;ZnyTe verify improved structural properties of Hgi _a :Cda .Te on the addition of zinc . Results for the composition dependence of hardness are also presented for the III -V alloys InxGai _a ;As , Gaa ;Ini _a .Sb , Ala .Ini _a :Sb , Gaa ;Ini _a ;P , and Ala ;Ini _a .As and compared with experimental data where available .
URI: http : / /hdl .handle .net /2346 /9573
Date: 1990-05

Citation

Ekpenuma, Sylvester Nwabuzor Electronic properties and microhardness of semiconductor alloys. Doctoral dissertation, Texas Tech University. Available electronically from http : / /hdl .handle .net /2346 /9573 .

Files in this item

Files Size Format View

There are no files associated with this item.

This item appears in the following Collection(s)

Show full item record

Search DSpace

Advanced Search

Browse