Investigation on physical properties of polycrystalline nickel sulphide films grown by simple & economical screen-printing method

Nickel sulphide (NiS) films offer a wide range of applications in solar cells, sensors, IR detectors and as an electrode in photoelectrochemical storage devices. In present investigation, nickel sulphide was synthesized by mechanical alloying and thick films were deposited on glass substrate by simple and economical screen-printing method followed by sintering process. The structural, morphological, elemental, optical and electrical properties of the prepared films were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive x-ray analysis (EDAX), UV-VIS-NIR spectroscopy and DC electrical resistivity measurement. XRD studies revealed the polycrystalline nature of films, having hexagonal structure with preferential orientation of grains along (100) plane. The FE-SEM image indicates that the film bears compact surface morphology with nearly spherical clusters. The EDAX analysis confirms the presence of Ni and S elements in prepared films. The optical properties of the films were investigated through reflectance measurement. The films were found to have a direct energy band gap of around 0.56 eV. The DC electrical resistivity of films were measured in vacuum by two probe technique and was found to be of the order of 104 Ω cm. All these properties indicate the suitability of these films for device applications.