Influence of air annealing on the structural, morphological, optical and electrical properties of chemically deposited ZnSe thin films

Zinc selenide nanocrystalline thin films are grown onto amorphous glass substrate from an aqueous alkaline medium, using chemical bath deposition (CBD) method. The ZnSe thin films are annealed in air for 4 h at various temperatures and characterized by structural, morphological, optical and electrical properties. The as-deposited ZnSe film grew with nanocrystalline cubic phase alongwith some amorphous phase present in it. After annealing metastable nanocrystalline cubic phase was transformed into stable polycrystalline hexagonal phase with partial conversion of ZnSe into ZnO. The optical band gap, Eg, of as-deposited film is 2.85 eV and electrical resistivity of the order of 106-107 Ω cm. Depending upon annealing temperature, decrease up to 0.15 eV and 102 Ω cm were observed in the optical band gap, Eg, and electrical resistivity, respectively.