Thickness dependent physical properties of chemically deposited nanocrystalline MgSe thin films deposited at room temperature by solution growth method

Chemical bath deposition method has been employed to deposit nanocrystalline magnesium selenide thin films of thickness 104-292 nm onto glass substrates at room temperature. The deposition bath consists of magnesium chloride, triethanolamine (TEA) and selenium dioxide. The as deposited films were characterized by X-ray diffraction, scanning electron microscopy (SEM), atomic force microscopy (AFM), optical absorption, electrical resistivity and thermo-emf measurements. The X-ray diffraction (XRD) studies revealed that the crystallinity of the magnesium selenide thin film increases with thickness. SEM studies reveal that MgSe films exhibit uniform distribution of round shaped grains over the entire substrate surface.The optical band-gap and electrical resistivity of MgSe film decrease as the film thickness increases. Such type of dependence is attributed to the quantum size effect that is observed in nanocrystalline semiconductors.The thermo-emf measurement confirms its p-type conductivity.