Effect of rm Cd 0.9 rm Zn 0.1 rm Te : In Crystals Annealing on Their High-Temperature Electrical Properties

We studied the electrical properties of rm Cd 0.9 rm Zn 0.1 rm Te : In (CZT) single crystals with [ rm In ] = 3 ast 10 15 Unknown character rm at / cm 3 at its high-temperature point-defect (PD) equilibrium state under a Cd overpressure ( rm P rm Cd ) . We detailed the influence of thermal treatment and the deviation of stoichiometry on the electron concentration, observing unexpectedly high conductivity and an increase in free-electron density ( similar to 1.5-2 orders of magnitude) when annealing the sample at 770 K under a Cd vapor pressure (0.01 atm.). Prolonged exposure of the samples under these conditions lowered the electron density by two approximately orders-of-magnitude until it approached the intrinsic value. The electron mobility after such treatment increased to CZT's maximal values at similar to 460 K (650-700 rm cm 2 / ( rm V ast rm s ) ). Therefore, such annealing can be effective in assuring high-resistive CZT detectors after crystal growth, or by special treatment, thereby eliminating the inclusions. We analyzed these data in the framework of Kroger's theory of quasi-chemical reactions, and compared the findings to those obtained for undoped CdTe.