Structural and optical studies of synthesized semiconductor NixZn1-xS nanostructure thin films for optoelectronic device applications

Abstract

Transition metal ions like nickel-doped Zinc Sulphide semiconductor materials have a wide range of optoelectronic device applications. However, the doping concentration effect on the properties of NixZn1-xS has not been reported. This study, therefore, investigated the effects of nickel (Ni) doping concentration on the structural and optical properties of synthesized Ni_xZn_1-xS nanostructured thin films prepared by the low-cost Chemical Spray Pyrolysis (CSP) technique. NixZn1-xS nanostructured thin films with a thickness of 320nm and different mole ratios (ϰ = 0.00, 0.02, 0.04, 0.06 and 0.08,) were grown by the use of spray solution on hot glass substrates at a temperature of 300 oC using CSP technique. The spray solutions contain nickel acetate, zinc acetate, and thiourea as precursors for Nickel, Zinc, and Sulphur, respectively. The influences of Ni doping concentration on the structural, optical, and morphological properties were investigated using X-ray diffraction (XRD), Ultraviolet-Visible spectroscopy (UV-Vis), and Scanning Electron Microscopy (SEM) respectively. The XRD analysis indicated that all the prepared films retained the ZnS cubic zinc blend structure. SEM results show that the films are composed of well-crystalline grains with various shapes and are densely bound to each other. The UV-Vis spectroscopy shows that transmittance is moderately high and increases with increasing Ni content. The average transmittance of Ni_xZn_1-xS are 61.3, 62.8, 63.9, 67.6 and 69.6 % for x = 0.00, 0.02, 0.04, 0.06 and 0.08, respectively. The bandgap of Ni-doped ZnS samples is narrow compared to the undoped and the value increases gradually with increasing Ni concentration. Based on the results obtained, with enhanced structural and optical properties, Ni_xZn_1-xS films could be useful materials for optoelectronic applications.