In order to meet the requirements for the device design of radiation detectors, CdZnTe (or Cd1−xZnxTe) crystals grown by vertical Bridgman method often need subsequent annealing to increase their resistivity. This treatment involved a diffusion process. Thus, it was meaningful to relate the change of resistivity to the diffusion parameters. A model correlating resistivity and conduction type of CdZnTe with the main diffusion parameter - the diffusion coefficient - was proposed. Combining the model with analysis of the present experimental data gave, DCd = 1.464 x 10−10, 1.085 x 10−11 and 4.167 x 10−13cm2/s as the values of the Cd self-diffusion coefficient in Cd0.9Zn0.1Te at 1073, 973 and 873K, respectively. These data coincided closely with the Cd self-diffusion coefficient in CdTe reported by various authors. With these data, the effects of annealing time on the change of resistivity and conduction type for Cd0.9Zn0.1Te wafers, which were annealed in saturated Cd vapour at 1073, 973 and 873K, were simulated, and good consistency was found. These results suggested an alternative way to obtain the diffusion coefficient in semiconductor materials and also permitted quantitative analysis of the diffusion process and prediction of the annealing results.

Study of the Effect of Cd-Diffusion Annealing on the Electrical Properties of CdZnTe. W.Li, Z.Cao, B.Zhang, F.Zhan, H.Liu, W.Sang, J.Min, K.Sun: Journal of Crystal Growth, 2006, 292[1], 53-61