Structural, optical and electrical properties of In2Se3 thin films formed by annealing chemically deposited Se and vacuum evaporated In stack layers

Indium selenide thin films were prepared by annealing the Se–In stack layers in high vacuum. Selenium film was deposited using chemical bath deposition and indium film, using vacuum evaporation. Annealing temperatures were varied from 373 to 723 K. Properties of these films were investigated using different analytical techniques. X-ray diffraction studies revealed that polycrystalline and amorphous γ-In2Se3 films were obtained depending on the annealing temperature. Both dark and photoconductivity of the films were found to decrease with increase in annealing temperature. Films formed at 373 K were having optical band gap 1.84 eV and maximum photoconductivity, while those formed at 723 K were found to have band gap 2.09 eV and showed minimum photoconductivity. From Hall measurements, it was observed that type of conductivity of the films depend upon the annealing temperature.