Zn-doping effects on ultrasonically spray-pyrolyzed CuO thin films: Interplay between material properties and gas sensing performance

In this study, zinc-doped copper oxide thin films were synthesized using the ultrasonic spray pyrolysis (USP) method and systematically characterized to evaluate their structural, morphological, optical, and gas-sensing properties. X-ray diffraction (XRD) confirmed the successful incorporation of Zn into the CuO lattice, revealing modifications in crystallinity and phase composition. Scanning electron microscopy (SEM) provided insights into surface morphology, and X-ray photoelectron spectroscopy (XPS) was employed to investigate the chemical states of Zn and Cu, confirming Zn substitution in the CuO matrix. Photoluminescence (PL) spectroscopy was utilized to analyze defect states and recombination dynamics, revealing changes in optical emission due to Zn doping. UV-Vis spectroscopy demonstrated a tunable optical absorbance and band gap characteristics with increasing Zn concentration. Gas sensor measurements were conducted to assess the films' sensitivity, and response time toward various hydrogen gas. The zinc-doped copper oxide thin films exhibited modified gassensing performance compared to the pure copper oxide samples attributed to improved carrier concentration, oxygen vacancy formation, and surface reactivity. These results suggest that Zn doping effectively tailors the properties of CuO thin films for potential applications in gas sensor technology.