Preparation and hydrothermal annealing of pure metastable β-MnS thin films by chemical bath deposition (CBD)

Pure metastable β-MnS thin films have been deposited by chemical bath deposition (CBD) method and subsequently annealed in a Na2S solution (denoted as hydrothermal annealing). The effects of preparative parameters and hydrothermal annealing on structure, morphology and optical property of the films have been investigated. Experimental results indicate that the crystalline β-MnS thin films can be prepared at a low concentration of Mn and S ions without using any organic chelator. The as-deposited β-MnS can be transformed to γ-phase MnS after the hydrothermal treatment in an autoclave at 200 °C for 1 h. The estimated Eg values are in the range of 3.15–3.18 eV.