Experimental Data on P-T-X Phase Diagrams and Non-stoichiometry

Abstract

II–VI semiconductor compounds are used for infrared, X-ray and γ-ray detection, in thin film solar cells, photo-refractive and blue/UV emission devices [118]. CdTe and Cd–Zn telluride, used as detectors for direct transformation of high-energy radiation to electrical signals, create a new generation of efficient detectors for medical applications, such as tomography. CdZnTe is used as a buffer layer in heteroepitaxy of mercury-cadmium telluride and as a substrate for epitaxial technology of (Hg,Cd)Te, the most important semiconductor material for infrared detector applications [119]. The next generation of infrared detection devices demands further improvement in material technology. These applications require high-quality multilayer heteroepitaxial structures with buffer layers serving to overcome the adverse effects of lattice mismatch, in particular, between Si or GaAs substrates and the active II–VI layer [120]. The lattice constant of (Cd,Zn)Te can be adjusted by changing the content of ZnTe to match the lattice of the (Hg,Cd)Te epilayer [121]. Some of the applications of II–VI bulk single crystals, according to P.Rudolph [122], are presented in Table 2.