Thermal and compositional defects in chemical spray pyrolysed indium selenide (In2Se3) thin films: Effects on film properties

Abstract

Polycrystalline In2Se3 semiconducting thin films were synthesized by chemical spray pyrolysis and their properties investigated. Strong dependence of structural and opto-electronic properties on film composition was observed. Absorption coefficient (α) at normal incidence was determined and an optimised direct optical band gap (Eg) of 1.92 eV was obtained at a substrate temperature (Tsub) of 673 K. Whereas low Tsub favoured incorporation of impurities in the films, elevated Tsub had the effects of introducing textural and structural defects with modifications in the film properties. The crystallinity of the films increased with switch from chalcogen rich to chalcogen deficient films.