EFFECT OF OXYGEN RATIO ON THE STRUCTURE, OPTICAL AND ELECTRICAL PROPERTIES OF NiO THIN FILMS

Abstract

Nickel oxide thin films have potential applications in various fields, particularly photovoltaics. In this study, nickel oxide thin films were deposited on glass substrates by the sputtering method at 100 °C with varying oxygen ratios (O₂/(Ar+O₂) x 100%). When the oxygen ratio was changed from 30% to 70%, the film’s structural, optical, and electrical properties were affected significantly. As the oxygen concentration increased, the crystallinity decreased, and the films became nearly amorphous at an oxygen concentration of 70%; the size of the crystalline particles decreased gradually. All NiO films deposited in the range of 30-70% oxygen had p-type semiconductor properties. The carrier mobility of the NiO films was relatively high, ranging from 5.384 x 10¹⁹ - 4.339 x 10²¹ cm^-3, suitable for hole transport applications. These results suggest that nickel oxide thin films have potential applications in optoelectronic devices, particularly in next-generation thin-film solar cells.