Structural, morphological, optical and luminescence investigations of chemical bath deposited Ni:ZnS thin films

Nickel doped zinc sulfide (Ni:ZnS) thin films are deposited on glass substrates by chemical bath deposition (CBD) for different Ni concentrations (0, 6, 12 and 18 at%). X-ray diffraction (XRD) patterns of undoped and Ni doped layers show a cubic structure with (111) preferred orientation. For the highest Ni concentration an impurity phase is detected and assigned to NiS compound. Fourier transform infrared (FTIR) analysis proves the existence of some residues in the films. X-ray photoelectron spectroscopy (XPS) reveals the formation of ZnS. The morphological study by scanning electron microscopy (SEM) shows important changes in layers topography. Transmittance (T) and reflectance (R) data reveal an enhancement for 6 at% and 12 at% dopant concentrations. Finally, photoluminescence (PL) properties show a decrease of the emission intensity with an increment of Ni content until 12 at%. Then, an increase of the PL intensity is observed with further increase of Ni amount.