The growth of high resistivity CdTe and (Cd,Zn)Te is successfully performed with different kinds of doping. In the literature intentionally undoped as well as doped crystals are presented with resistivities up to 10 10 Ωcm. In this paper we review the growth of high resistivity CdTe and (Cd,Zn)Te. The mechanism of compensation is discussed regarding the different dopants and deep levels, which seem to be responsible for the high resistivity. A common compensation model explains the high resistivity by deep levels. The doping and the influence on the compensation mechanism is compared for several elements like tin, germanium and chlorine. The material properties and the crystal quality of undoped and doped CdTe as well as (Cd,Zn)Te are shown. Dedicated to Professor K. W. Benz on the occasion of his 65th birthday.

Because of its ideal band gap, high density and high electron mobility-lifetime product, cadmium zinc telluride (CdZnTe or CZT) is currently the best room-temperature compound-semiconductor X- and gamma-ray detector material. However, because of its innate poor thermo-physical properties and above unity segregation coefficient for Zn, the wide spread deployment of this material in large-volume CZT detectors is still limited by the high production cost. The underlying reason for the low yield of high-quality material is that CZT suffers from three major detrimental defects: compositional inhomogeneity, high concentrations of dislocation walls/sub-grain boundary networks and high concentrations of Te inclusions/precipitates. To mitigate all these disadvantages, we report for the first time the effects of the addition of selenium to the CZT matrix. The addition of Se was found to be very effective in arresting the formation of sub-grain boundaries and its networks, significantly reducing Zn segregation, improving compositional homogeneity and resulting in much lower concentrations of Te inclusions/precipitates. Growth of the new quaternary crystal Cd1−xZnxTe1−ySey (CZTS) by the Traveling Heater Method (THM) is reported in this paper. We have demonstrated the production of much higher yield according to its compositional homogeneity, with substantially lower sub-grain boundaries and their network, and a lower concentration of Te inclusions/precipitates.