Investigations of Schottky barrier structures in compound semiconductors: I. HgTe on CdTe: a lattice-matched Scottky barrier. II. Au-Cd barriers to CdTe. III. Au barriers on In(x)Ga(1-x)P

Citation

Kuech, Thomas F. (1981) Investigations of Schottky barrier structures in compound semiconductors: I. HgTe on CdTe: a lattice-matched Scottky barrier. II. Au-Cd barriers to CdTe. III. Au barriers on In(x)Ga(1-x)P. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-12122006-090129

Abstract

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i) The Au Schottky barrier height to [...] was measured as a function of alloy composition. The Au barrier, [...], to [...] was found to be independent of composition. The barrier, [...], was determined by the relation [...] where [...] is the band gap energy and [...] is the measured barrier height to [...]. It has been observed that the Au barrier height to p-type material for most compound semiconductors is determined by the anion. This dependence on the anion of the compound has now been seen to extend to the alloy system [...] measured here.

ii) The Schottky barrier height of Cd, Au, and Au-Cd alloys was determined on vacuum cleaved surfaces of n-CdTe. A large barrier of 0.92 eV was found in the case of the Au-Cd alloy contacts. Contacts made with elemental Cd or Au gave barrier heights of 0.45 and 0.65 eV, respectively. The increased barrier height found on Au-Cd alloy contacts may be related to recent UHV observations on Schottky barrier formation where crystal defects play a role in determining the observed barrier height.

iii) HgTe-CdTe lattice matched heterojunctions were formed by the epitaxial growth of HgTe on CdTe substrates using a new low temperature metal organic chemical vapor deposition (MOCVD) technique. These heterojunctions combine features of the Schottky barrier structure, due to the high carrier concentrations found in the semi-metallic HgTe, with the structural perfection present in a lattice matched heterojunction. The measured Schottky barrier height varied from 0.65 to 0.90 eV depending on the details of the HgTe growth procedure used. Two models of the HgTe-CdTe heterojunction are presented which account for the observed variation in barrier height.

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