Effect of nickel doping on structural, morphological and optical properties of sol–gel spin coated ZnO films

Abstract

As a versatile semiconductor material, Ni doped ZnO thin film is studied mainly for its ferromagnetic properties, while the electrical and optical performances are few. It is believed that doping in ZnO thin films can improve the crystalline quality or obtain better optical, electrical or ferromagnetic properties. In this paper, the main research is focused on the preparation process and optical properties of transparent ZnO thin films doped with different Ni concentrations. The proposed research investigates the ZnO thin films doped with different Ni concentrations that are important in understanding the structural and optical performances of Ni doped ZnO thin film. The transparent ZnO thin films doped with different Ni concentrations were deposited on glass substrates via sol–gel technique using zinc acetate dehydrate and nickel chloride as precursor. The morphology and microstructural properties of undoped and Ni doped ZnO thin films were studied by X-ray diffraction, scanning electron microscopy (SEM), atomic force microscopy and X-ray photoelectron spectroscopy. The optical properties of the thin films were determined by photoluminescence (PL) and UV–visible spectroscopy. The results indicate that the obtained films have smooth surfaces and are of good crystal quality, which have a pure hexagonal wurtzite ZnO without any Ni related phases. The surface roughness and mean grain size of Ni doped ZnO thin films are sensitive to Ni concentrations. The undoped and Ni doped ZnO thin films with high transmittance in the visible region show room temperature PL. The Ni doped ZnO thin films display room temperature PL at blue and green emissions. Its good crystal quality and optical performances make it a promising transparency and visible luminescence thin film for transparent multispin electronic devices.