An analysis of the Cd-Te pressure-temperature-composition phase diagram revealed a deviation, in CdTe stoichiometry, in the Te-depletion direction between 450 and 550C. Control over the composition, via intrinsic defects, and over the atmosphere and cooling rate therefore yielded a method for the intrinsic doping of CdTe at relatively low temperatures. The quenching of CdTe, following annealing in a Te atmosphere at 400 to 550C, led to p-type conductivity with a hole concentration of 2 x 1016/cm3. Slow cooling, after annealing at 550C in Te or vacuum, increased the hole concentration by an order of magnitude; as compared with quenching at the same temperature. This increase was explained by a reaction between Te vacancies and Te interstitials.

Low Temperature, Post-Growth Self-Doping of CdTe Single Crystals Due to Controlled Deviation from Stoichiometry. V.Lyahovitskaya, L.Chernyak, J.Greenberg, L.Kaplan, D.Cahen: Journal of Applied Physics, 2000, 88[7], 3976-81