Growth of ZnO Ns Nanosheets: Pioneering Synthesis via Wet Oxidation Method for Photodetector Application

The properties of Zinc oxide nanosheets (ZnO-NS) synthesized on Si (100) substrate using a two-step wet-oxidation process that involves RF magnetron sputtering of Zn thin films (~ 100 nm) followed by oxidation in a water vapor atmosphere are investigated in this work in relation to different wet-oxidation durations (2, 3, 4, and 5 hours) at 300°C. According to Field Emission Scanning Electron Microscopy (FESEM), stress-induced splitting and free energy reduction caused the change from no nanostructures at 2 hours to huge nanosheets at 3 hours, followed by smaller, denser, and uniformly distributed nanosheets at 4 and 5 hours.A wurtzite ZnO structure with increased (002) peak intensity and decreased compressive strain (-0.116% to -0.081%) over extended periods of time was confirmed by X-ray diffraction (XRD). High visual transparency, substantial UV absorption at 380 nm, and a band gap of about 3.256 eV were all revealed by UV-Vis spectroscopy. With enhanced crystal quality and decreased sulfur vacancy-related green emission at longer oxidation durations, photoluminescence (PL) spectra displayed dominating near-band-edge emission (378–380.8 nm). At higher bias voltages (+ 3 to + 7 V), photodetector I-V characteristics showed non-ohmic behaviour, improved photosensitivity, and optimal photocurrent at 4 hours. These results demonstrate how important oxidation time is when customizing ZnO nnanosheets for optoelectronic and photocatalytic uses.