STRUCTURAL STABILITY OF ZN-CONTAINING II-VI SEMICONDUCTOR ALLOYS - MICROHARDNESS CALCULATIONS

The lattice strengthening effects of the addition of ZnTe to HgTe, CdTe, and HgCdTe are investigated using a solid-solution hardening model. The microstructural hardnesses of the resulting alloys HgZnTe, CdZnTe, and HgCdZnTe are calculated and compared with that of HgCdTe obtained in the same model. Good agreement with available experimental data is obtained for the hardness variation with composition for CdZnTe, HgZnTe, and HgCdTe. These calculations show that the alloys containing Zn have superior hardnesses to HgCdTe. They thus verify the experimental observation that these alloys are structurally superior to HgCdTe. The microhardness of HgCdZnTe for a fixed Cd composition of 0.2 is predicted to be slightly greater than that of HgZnTe for all Zn compositions. On the other hand, for simultaneous variation of the Cd and Zn compositions such that the band gap is constant and in the infrared regime, HgZnTe is predicted to always be harder than HgCdZnTe.