Abstract
Se(0.8)S(0.2) glassy films of thickness 583 nm have been prepared by thermal vacuum evaporation technique. Annealing of the films shows that the crystallization process starts at T = 333 K and nanostructured film is formed. The increase of the annealing temperature to 373 K increases the crystallite size to 24 nm. Orthorhombic crystalline system was identified for the annealed films. SEM micrographs show that films consist of two parallel surfaces and the thickness was determined by cross section imaging. The optical transmittance is characterized by interference patterns as a result of these two parallel surfaces, besides their average value at longer wavelength decreases as a result of annealing process. The band gap, E(g) is red shifted due to crystallization by annealing. The change of E(g) from the amorphous value to the crystalline one is not sharp. A relatively slow decrease in E(g) intermediate annealing temperature was observed, This change was explained in the energy gap confinement behavior of the nanostructured films and the phenomena was discussed in the Brus's model. The optical refractive index increases suddenly when the system starts to be crystallized by annealing.