In this work, a simple solution synthesis route for CoSe nanostructure thin films using the chemical bath deposition method is presented. The ions concentration role that affects the evolution of the nanostructure thin film configuration and optical band gap in CoSe nanoparticle arrays are investigated. The experimental data showed that the ions concentration can affect the optical band gap, surface topography, and configuration of a thin layer in the same way as they affect the optical band gap and thin film thickness. Derivation ineffective thickness method has been employed for optical band gap determination and index transitions without any presumption about the transition nature. The useful numerical data for characterization of the surface topography extracted from atomic force microscopy data has been examined. The influence of the ions concentration on the 3-D surface morphology of cobalt selenide (CoSe) nanostructure thin films prepared by chemical bath deposition method has been considered.
