EFFECT OF ANNEALING ON THE STRUCTURE AND OPTICAL PROPERTIES OF a-Se-Sb-Ag THIN FILMS

摘要

Se70Sb20Ag10bulk sample was obtained using conventional melt quenching technique. Thin films of a-Se70Sb20Ag10were prepared by vacuum evaporation technique in a base pressure of 10-4mbar onto well-cleaned glass substrates. The structure of the as-prepared and annealed films has been studied by X-ray diffraction. These studies show that there is no appreciable change in structure when annealed in the temperature range of 323-363K, however, when annealed above 373K the formation of some polycrystalline structures in the amorphous phases is seen. The optical transmission of these films has been studied as a function of photon wavelength in the range 400-900nm. It has been found that the optical energy gap first increases with annealing temperature upto 323K then continuously decreases with increase in annealing temperature and sharply decreases near crystallization temperature. The temperature dependence of electrical conductivity of the as-prepared and annealed thin films has also been studied. It has been found that the electrical activation energy follows the trend of the optical energy gap as the annealing temperature increases