NANOCRYSTALLINE ZnO THIN FILM FOR GAS SENSOR APPLICATION

Nano-crystalline (NC) materials exhibiting small particle size and large surface area may be applied for gas sensors, for which an excellent surface effect is required. Thin films of zinc oxide (ZnO) have been deposited onto glass substrates using a simple and inexpensive ultrasonically spray pyrolysis technique. Aqueous methanolic solution of zinc acetate was used as a spraying solution. The concentration of the solution was 0.1 M. The films prepared at different substrate temperature were uniform and well adherent to the substrates. X-ray diffraction (XRD) studies showed that all the films were polycrystalline in nanosize scale. The SEM photographs reveal the nano-size of the constituents. The electrical resistivity of the films was found to be dependent on the deposition temperature. The room temperature electrical resistivity was found to be varying in the range 10(-5) to 10(-6) ohm cm(-2). The sample resistance is measured with the presence of CH4 in Ar carrier gas. The obtained responses of the samples were studied where our data were analyezed on the basis Yamoze SnO2 sensor.