Synthesis and Methane Gas Sensing Study of Uniform Zinc Oxide Nanoparticles and Thin Film

In this study, zinc oxide (ZnO) nanoparticles and their thin film were synthesized using co-precipitation and spin coating techniques, respectively. Spherical nanoparticles measuring 10–120 nm and thin film having particle with a diameter of 10–100 nm were synthesized. The electrical properties of the synthesized nanoparticles were evaluated using the KEITHLEY semiconductor characterization system. The structure, phase identification, and morphology of the nanoparticles investigated by X-ray diffraction, Raman, and scanning electron microscope techniques were employed. The results confirmed that the ZnO nanoparticles had a hexagonal wurtzite structure. Additionally, gas sensing measurements were conducted using a locally made sensing chamber. The response of nanoparticles and their thin film were observed at varying concentrations of methane gas in the chamber. Response of the thin film as sensor is greater, fast and consistent as compared to nanoparticles sensor. Our study reveals best sensor having response (R_a/R_g) of 1.37 for 100 ppm of CH₄ at 140 °C as compared to previous reported studies.