The variation in optical gap of amorphous In33Se33Sb33 thin films with temperatures of heat treatment

Amorphous thin films of the ternary compound In₃₃Se₃₃Sb₃₃ have been produced by a vacuum evaporation technique. The optical gap Eg^opt of In₃₃Se₃₃Sb₃₃ thin films is measured as a function of temperature of heat treatment. It was found that the optical gap has a higher value than that of the binary compound In₅₀Se₅₀ at the initial stages of heat treatment, but after a particular temperature (423 K) of heat treatment, the value of optical gap decreases appreciably in the case of In₃₃Se₃₃Sb₃₃ thin films, while it increased in the case of In₅₀Se₅₀ thin films.