PROPERTIES OF CADMIUM TELLURIDE CONTAINING IMPURITIES INTRODUCED DURING SPRAY-PYROLYSIS

Thin-film CdTe was prepared in three steps: spray pyrolysis to form CdO, conversion of CdO to CdS, and conversion of CdS to CdTe. It was also possible to prepare CdTe directly from CdO, but longer reaction times were required. Efficiencies of spray deposition were as high as 25%. The film thickness and uniformity were reproducible, and stoichiometric CdTe films were obtained. When As and P were incorporated into the films, the CdTe conductivity was increased from 3 to 5 orders of magnitude. The lowest resistivity value obtained for these films was 10(3) Omega cm, mobilities ranged up to 35 cm(2) V-1 s(-1). High concentrations of Ag and Cu were required to reduce the resistivity of the CdTe films. In these cases, the films may be composite materials with material segregation. The incorporation of Ga had no effect on the resisitivy. CdCl2 treatment of CdTe lowered resistivity by 1 order of magnitude, and hole density increased.