Abstract
Thin films of a-Se88Te12-xAl-x(x = 0,5,10) have been deposited by physical vapour condensation method. Optical properties of as-prepared thin films of a-Se(88)Te(12-x)Al(-x)and laser irradiated thin films have been studied. These thin films contain nanoparticles of average diameter 50 nm as observed by Scanning Electron Microscopy (SEM). After laser irradiation, the particle size increases which has been verified by SEM investigations. XRD patterns suggest the amorphous nature of as-prepared thin films. In case of laser irradiated samples, the structure changes from amorphous to polycrystalline with presence of significant peaks in XRD patterns of a-Se88Te7Al5&a-Se88Te2Al10 have been observed. As-prepared thin films as well as laser irradiated thin films show a decrease in optical band gap with the increase in Al concentration. The optical band gap also decreases after laser irradiation. The optical constants (refractive index (n) & extinction coefficient (k)) have also been calculated and the variation with photon energy and metal (Al) concentration has been studied.