Investigation of physical and photodiode properties of Ir-doped NiO films

In this paper, we focus on pure and Ir-doped NiO films fabricated on glass and n-Si substrates via sol-gel spin coating. A comprehensive investigation on the structural, optical, electrical and morphological properties of the films was carried out. The results obtained from this study depending on the increasing Ir doping exhibit a decrease in the crystallite size from 27.6 nm to 16.7 nm, a decrease in the optical band gaps obtained by Tauc plot and Kubelka-Munk methods from 3.71 eV to 3.67 eV and 3.43 eV–3.00 eV and an increase in the Urbach energy values from 0.16 eV to 0.37 eV. In the context of diode analysis, an increase in the ideality factor was observed, along with a decrease in both barrier height and RR. The diodes obtained with Ir-doped NiO films on n-type Si have decreased ideality factors, barrier heights and RR ratios due to Ir doping.