Structural and Gas Sensing Properties of Annealed ZnO Thin Film

Annealed ZnO thin film at 400 °C for two hours was deposited on a glass substrate by using pulsed laser deposition (PLD). The structural properties of the annealed ZnO thin film were studied by XRD, TEM and SEM. Gas sensing properties for different gases such as H₂ and LPG were investigated. Applying XRD the size of the nanocrystals is found to be 10.61 nm. SEM of the thin film consisted of many grains distributed uniformly throughout the surface. An annealed ZnO thin film sensor showed the typical n-type semiconducting behavior in the case of H₂ and LGP gases at low and high operating temperature range, respectively. When working at 50 and 140 °C the sensor exhibits very good dynamic response–recovery characteristics to H₂ and LGP, respectively. These results along with a simple fabrication process demonstrate that the annealed ZnO thin film at 400 °C for two hours is promising for developing low cost and high performance H₂ and LPG sensors. The low cost of the sensor element fabrication, high H₂ and LPG sensitivity, fast response and quick recovery make the entire fabrication process a front-runner and cost-effective for the production of annealed ZnO thin film H₂ and LPG sensors.