Effect of annealing on the optical quality of AgGaS₂ and AgGaSe₂ single crystals

Abstract

Single crystals of AgGaS₂ and AgGaSe₂ were grown by a modified Bridgman-Stockbarger technique. Pieces of sizes 10 mm × 6 mm × 4 mm and 11 mm × 6 mm × 5 mm of AgGaS₂ and AgGaSe₂ free from lamellar twins, were cut from the crystals for detailed investigations. The results of infrared transmittance and absorbance measurements indicate that the optical quality of the annealed crystals was much better than that of the as-grown crystals. Experiments on thermal etching were also carried out to study the microscopic defects in the crystals.