Improved UV photodetector performance of NiO films by substitutional incorporation of Li

[Display omitted] •We describe the lattice structure of substitutional Li+ in Ni2+ vacant site of NiO.•Possible mechanism of enhanced intrinsic p-type conductivity is projected.•The superior charge carrier generation is obtained through Li incorporation.•Achieve the higher photodetector performance in Li0.2Ni0.8O sample. In this study, NiO and Li0.2Ni0.8O (LNO) thin films are successfully deposited by sputtering technique. X-ray photoelectron spectroscopy (XPS) analysis revealed the existence of Ni vacancies. Here, we fabricated metal-semiconductor-metal (M-S-M) structure for exploring the ultra-violet (UV) photodetector (PD) performance. The impact of interstitial oxygen and substitutional incorporation of monovalent Li+ ion in Ni2+ sites of NiO on UV photodetector performance are explored. In a word, LNO exhibited superior responsivity (0.218 A/W) and detectivity (0.467 × 1012 Jones) even at lower power density of 0.31 mW/cm2.