Examining the impact of Fe³⁺doping on the ultraviolet sensing capabilities of NiO thin films fabricated using the nebulizer spray pyrolysis method

Nano layered pristine and Fe-doped Nickel Oxide (NiO) thin films with varying dopant compositions (0, 1, 2, 3, 4 and 5 wt%) were effectively fabricated over glass substrates via the nebulizer spray pyrolysis method, with emphasis on their potential application in photonic UV sensors. The influence of Fe concentrations on the structural, morphological, distribution of elemental concentration, photoluminescence, optical properties and photo sensing attributes of the devices were systematically investigated using a suites of characterization techniques. X-ray diffraction analysis confirmed the effective integration of Fe within the NiO lattice, exhibiting face centred cubic geometry with a prominent peak along (111), consistent across all the films. The formation of uniform, smooth and dense nano-grain structures with sand like morphology, exhibiting a crack- free surface were confirmed by field emission scanning electron microscopy (FESEM) images. The band absorbance spectra displayed a band gap narrowing from 3.46 eV to 3.36 eV with increasing Fe doping concentrations from 0 to 5 %. The photoluminescence (PL) spectra exhibited dual emissions, comprising band-edge and defect – related emissions, consistently observed across the films. The 3 wt% Fe doped NiO thin film exhibited outstanding photodetector performance characterised by a high responsivity of 37.5 × 10^–2 AW^-1, detectivity of 131 × 10⁸ Jones and external quantum efficiency of 88 %. Additionally, it demonstrated the shortest rise and fall times along all the fabricated photo-detectors. This established research work presents a promising pathway for future advancements in photo sensor industry.