Low Defect LWIR Substrates by the Detached Growth Method

This proposal is focused on the development of a novel method for the growth of low-dislocation-density, high-purity, and low-precipitate-concentration CdZnTe and CdSeTe crystals for use as substrates for MCT detectors. This work is motivated by the observation that II-VI compound semiconductors grown detached from the containment wall in space, as well as other materials grown on earth, have exhibited significantly lower dislocation density and higher purity. This program will seek to grow detached Cd(Zn,Se)Te crystals through the development of a feedback-controlled detached growth process, where the signals generated by a non-intrusive sensor are used to maintain a detachment gap of the order of 50-100 microns between the growing crystal and the ampoule.