The composition effect on the thermal and optical properties across CdZnTe crystals

Abstract

Cd1-xZnxTe mixed crystals investigated in this work were grown from the melt by vertical Bridgman-Stockbarger method in the whole range of composition 0<x<1 that is from one binary crystal (CdTe) to another (ZnTe). The real composition of grown crystals was measured with SEM/EDS method along growth axis. The segregation coefficient of Zn in CdTe matrix has been evaluated as close to unity. The energy gap as a function of the composition was determined from transmission spectroscopy. Thanks to that bowing parameter of this ternary alloy was found to be 0.458. In this work for the first time the systematical study of thermal properties of Cd1-xZnxTe alloys from one binary crystal (CdTe) to another (ZnTe) grown by vertical Bridgman technique were undertaken. The thermal diffusivity and effusivity of investigated crystals were derived from the experimental data and allowed calculating the thermal conductivity. Diagrams of the thermal conductivity versus composition were analyzed applying model for mixed semiconducting crystals given by Sadao Adachi. Thanks to that contribution of the thermal resistivity arising from the lattice disorder to the total resistivity of the crystal has been determined.