Direct Observation of Precipitate Phenomena and Dislocations in Annealed CdS:Cu and CdS:Au Single Crystals

The procedure of high‐temperature annealing followed by quenching was used to produce significant changes in the microstructures of as‐grown CdS : Cu and CdS : Au single crystals. The use of optical microscopy enabled these changes to be directly observed with high resolution. The solubility of copper is retrograde, the maximum being about 0.2 w/o between 475° and 650°C; the maximum solubility of gold is less than 0.03 w/o. Annealing CdS : Cu between 700° and 1100°C causes temperature dependent microchanges that include the formation and growth of precipitates and the generation of dislocations by prismatic punching. In the case of gold, initial precipitates change only when crystals are annealed at or above 900°C. High‐temperature precursors of room temperature precipitates are identified from reversible changes in morphology, and unique, high‐temperature dislocation structures are observed. Gold also diffuses to the crystal surface where it forms characteristic epitaxial deposits.