Investigation of p-NiO/ n-Zn_(1-x) Sn_(x)O isotype heterojunctions fabricated via DC magnetron reactive sputtering

A bilayer heterojunction consisting of p-NiO/Zn_(1-x)Sn_(x)O (TZO) (x = 0.14) was grown via DC magnetron sputtering and the impact of Rapid Thermal Annealing (RTA) on its physical properties was evaluated. Structural, morphological, optical, and electrical analyses were performed to analyze the effects of RTA on the heterojunction. X-ray diffraction analysis confirmed the polycrystalline nature of both layers and scanning electron microscopy imaging depict the absence of cracks and pinholes in the grown layers. RTA treatment resulted in an increase in the visible region transmittance of the NiO/TZO heterojunction and a sharp absorption edge in the ultraviolet region was observed from the optical studies. Electrical properties such as rectification ratio, ideality factor, barrier height, and built-in potential were determined through dark current-voltage and capacitance-voltage measurements, which showed improvement in rectification ratio and barrier height after RTA. Impedance spectroscopy revealed a decrease in series resistance after RTA. These results contribute to the development of high-performance metal oxide-based heterojunction for next-generation photonic and electronic devices.