i) The Au Schottky barrier height to n - InxGa1-xP was measured as a function of alloy composition. The Au barrier, φp, to p - InxGa1-xP was found to be independent of composition. The barrier, φp, was determined by the relation φp + φn = φg where φg is the band gap energy and φn is the measured barrier height to n - InxGa1-xP. 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 InxGa1-xP 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.
