Preparation and Study the Electrical, Structural and Gas Sensing Properties of ZnO Thick Film Resistor

Thick films of AR grade ZnO were prepared on glass substrate by screen-printing technique. These films were dried and fired at different temperatures between 550 °C, 600 °C and 650 °C for one hour in air atmosphere. The gas sensing performance of thick films was tested for various gases. ZnO films showed larger response (sensitivity) to H^sub 2^S gas (100 ppm) at 250 °C for firing temperature 650 °C. The Morphological, Compositional and Structural properties of the ZnO thick films were performed by Scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDX) and XRD technique respectively. Chemical composition of ZnO film samples changes with firing temperature showing non-stoichiometric behaviours. XRD study indicated the formation of polycrystalline ZnO films with hexagonal wurtzite structure. The gas response (sensitivity), selectivity, response and recovery time of the sensor were measured and presented. [PUBLICATION ABSTRACT]