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 con ducting p- and n-type CdTe, by manipulating the native defect equilibria on ly, without resorting to external dopants. Quenching of CdTe, following its annealing in Te atmosphere at 350-550 degrees C, leads to p-type conductiv ity with hole concentrations of similar to 2 x 10(16) cm(-3) Slow cooling o f the samples, after 550 degrees C annealing in Te atmosphere, increases th e hole concentration by one order of magnitude, as compared to quenching fr om the same temperature. We explain this increase by the defect reaction be tween donors V-Te and Te-i. Annealing in Cd atmosphere in the 350-550 degre es 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 dif fusion. (C) 2000 Elsevier Science B.V. All rights reserved.