Charge-Transfer-Controlled Vaporization of Cadmium Sulfide Single Crystals. II. Effect of Copper Doping on the Evaporation Rate of the (0001) Face

The evaporation rate of copper‐doped CdS single‐crystal c face was measured in the temperature range 680°—740°C. The evaporation rate was decreased markedly with respect to that of the undoped crystals. The copper surface concentration dependence of the vaporization rate was studied by simultaneous diffusion of copper into, and vaporization of the crystal at the ($\text{0001̄}$ ) and (0001) crystal faces, respectively. The presence of copper impurity in the bulk of the crystal was found to also have an effect on the evaporation rate of CdS. The results were interpreted in terms of self‐compensation in CdS via sulfur‐vacancy formation, and copper‐ and sulfur‐vacancy diffusion toward the vaporizing surface. Copper doping rendered the crystal vaporization insensitive to light.