Journal of Crystal Growth, Vol.214, 1155-1157, 2000
n- and p-type post-growth self-doping of CdTe single crystals
Careful analysis of the Cd-Te P-T-X phase diagram, allows us to prepare conducting p- and n-type CdTe, by manipulating the native defect equilibria only, without resorting to external dopants. Quenching of CdTe, following its annealing in Te atmosphere at 350-550 degrees C, leads to p-type conductivity with hole concentrations of similar to 2 x 10(16) cm(-3) Slow cooling of the samples, after 550 degrees C annealing in Te atmosphere, increases the hole concentration by one order of magnitude, as compared to quenching from the same temperature. We explain this increase by the defect reaction between donors V-Te and Te-i. Annealing in Cd atmosphere in the 350-550 degrees C temperature range leads, in contrast to the annealing in Te atmosphere, to n-type conductivity with electron concentrations of similar to 2 x 10(16) cm(-3). We ascribe this to annihilation of V-Cd as a result of Cd-i diffusion.