Synthesis of NiO/Si Using Sol-Gel as a Photosensor

Recent studies have indicated that that the application of nickel oxide (NiO) regulator nano-films is growing. The sol-gel method has become the primary method for preparing NiO thin films. This paper describes a method to achieve optimum NiO thin films through this method. Nanostructured NiO nanoparticle (NP) films were successfully fabricated using the sol-gel method at different annealing temperatures as a photosensor device. This was carried out using a systematic change of parameters, such as the thermal annealing, to study the effect on the size of the metal oxide nanoparticles. The optical, structural and electrical properties of NiO nanoparticle films were characterised by ultraviolet-visible (UV-visible) and X-ray diffraction analyses. The results show that the films exhibit an average grain size depending on the annealing temperature. The optical properties revealed that the deposited films were p-type, and increasing the annealing temperatures leads to a shift in the maximum value of the absorption peak towards long wavelengths (red). This results in a drop in the energy gap as the annealing temperature increases. The voltage-current characteristics for both types of NiO/p-Si heterojunction (dark and illuminated) were investigated as a function of the annealing temperature. This study demonstrated that the best-estimated structural, optical, and electrical characterisations were achieved with NiO films at 650 °C.