Nanocrystallites in Bi–As–S system

Bi2S3–As2S3 composite formation was performed by two methods: by the direct insertion of Bi2S3 nanocrystals into a molten As2S3 glass which was further solidified and by the crystallization of a rapidly quenched (As2S3)1−x (Bi2S3)x glasses with x = 0.005, 0.01, 0.02 and 0.04 at different conditions. Fine tuning of the annealing of the quenched glass as well as the mixing of nanocrystals in to the molten glass resulted glass-crystalline composites with different amounts and distribution of 20–50 nm large Bi2S3 nanocrystals as well as larger, up to few micrometer long, needle-like crystals. Structural and optical investigations support the presence of the Bi2S3 crystalline phase in all composites. Optical absorption and the photoconductivity of bulk composite samples follow the structural changes of the structure in the amorphous and amorphous-crystalline phase. In addition, the 290 cm−1 characteristic band in Raman spectra may be used for tracing the formation of the nanocomposites.