Thickness dependence of the electrical and structural properties of (PbSn)Te epitaxial films

The electrical properties of epitaxial (PbSn)Te films were found to be strongly dependent upon film thickness up to a thickness of ∼5 μm. An analysis of the various scattering mechanisms indicated that the increase in the experimentally measured carrier mobility with thickness is due mainly to a decrease in the defect scattering. A TEM study showed that the defect structure in these films also changes dramatically with film thickness and growth time. The defect density is reduced by the annealing out of dislocations by slip; dislocation climb leads to formation of extended defect clusters and the reduced concentration of point defects by gettering. 3 figs., 8 refs