Photoconductivity studies in vanadium-doped CdTe and Cd1-xZnxTe

Abstract Semi-insulating Cd 1- x Zn x Te:V crystals, for x = 0.01, 0.04, 0.07 and 0.10, are investigated in comparison with CdTe : V i.e. for x = 0, and with undoped CdTe by spectral response of steady-state photoconductivity at various temperatures, mainly in the near infrared, and by thermal dependence of the intrinsic photoconductivity. The results, which confirm that V is indeed the dominant carrier donor, are discussed in terms of electronic transitions for the two vanadium charge states V 2+ and V 3+ , related to the zinc concentration. It is found that the magnitude of some of these transitions vary strongly with temperature due to a two-step photo-thermal ionization process.