Microstructural and optical properties of nanocrystalline MgS thin film as wide band gap barrier material

Magnesium sulphide (MgS) thin films have been successfully grown by electrochemical deposition process at room temperature. X-ray diffraction studies revealed that the films have distinct features of crystallinity. Prominent characteristic peaks corresponding to cubic structure were identified along (200) and (222) reflections. Surface morphology indicated that the grain sizes of the films ranging between 15 and 17 nm were uniformly distributed across the substrate. Post-deposition annealing enhanced the shape and particle size of the films. Growth height and surface roughness were obtained from atomic force microscope topographic images. Analysis of the optical data gave the values of energy band gaps of the three MgS thin films under study. Energy gaps of the annealed samples were estimated as 3.54 and 3.73 eV while that of as-deposited was given as 4.10 eV.