EFFECT OF HEAT-TREATMENTS ON AGGAS2 PHOTOLUMINESCENCE

Heat-treatments such as Ag2S- and Ga2S3-treatment and Ga dipping were performed and the effect was investigated by measuring the emission intensity of photoluminescence. After the Ag2S-treatment and Ga-dipping, the emission intensity due to free exiton significantly increased which indicates that the quality of single crystals was enhanced and the non-radiative recombination centers were reduced. By the Ga2S3-treatment, the emission intensities changed with an increase of Ga2S vapor pressure, which gave a clear evidence for the emission origins to be Ag and Ga vacancies. After the Ga-dipping, the intensity of red band decreased, supporting that the emission origin is the defect due to excess sulfur.