Preparation of Hg 1− xCd xTe (0.1≤ ×≤0.5) epitaxial layers by two-stage evaporation–condensation–diffusion method

Abstract

The present investigation is devoted to the further study of the two-temperature evaporation–condensation–diffusion (ECD) method. Experiments have been performed to determine the Hg vapour pressure influence on rates of HgTe evaporation and condensation, morphological peculiarities of the initial stages of Hg 1− x Cd x Te layer growth, and interdiffusion in the HgTe–CdTe system. It is shown that the classical ECD method for Hg vapour pressures higher than 4 atm becomes inefficient due to the several reasons discussed in this paper. We suggest a two-stage epitaxy process for Hg 1− x Cd x Te and other solid solutions. In the first stage, a structurally perfect layer with a desired thickness is formed at low Hg pressure. In the second stage, the Hg vapour pressure is fixed. This provides the necessary composition of the layer surface. High-quality Hg 1− x Cd x Te layers with the surface composition x s up to 0.5 are reproducibly obtained by this proposed technique.