Optical and structural properties of amorphous and heat treated In0.4Se0.6 film of different thicknesses

Abstract

The optical gap (E g opt ) of as-deposited In0.4Se0.6 film is found to increase with the thickness of the film. The optical gap attains a steady value after several heat treatments of the films at elevated temperatures. The values of optical gaps of In0.4Se0.6 films are found to depend on the temperature of the heat treatment. The effect of thickness and temperature of heat treatment on the optical gap of the film is interpreted in terms of creation or elimination of defects in the amorphous structure of In0.4Se0.6 film. X-ray diffraction spectra are taken for both as deposited and heat treated In0.4Se0.6 films. From the results related to the radial distribution functions of the specimens it is noted that in the case of In0.4Se0.6 a transition from amorphous to crystalline states takes place at 523 K and above. The results also show that both the optical gap and the coordination number decrease with increasing temperature of heat treatment. Therefore it is evident that the heat treatment improves the long range order of In0.4Se0.6 but reduces the coordination in the short range.