ZnO nanoparticulate thin film: preparation, characterization and gas-sensing property

ZnO thin films were prepared by sol-gel dip coating method using zinc acetate dihydrate and 2-ethanolamine as the starting materials. The powder and its thin film were characterized by X-ray diffractometer (XRD), atomic force microscopy (AFM) and IR spectra methods. The results indicated that the ZnO particles crystallized in the wurtzite phase, which were well-distributed in the films with the mean particle size of about 10 nm. The IR spectra of the gel and powders annealed at different temperatures were investigated. It showed that the vibration bands of N-H and mono-acetate diminished and the stretching mode of ZnO at 471 cm(-1) appeared after the dried gel annealed at 500 degreesC for 1 h. The diameter, D of ZnO particles in the monolayer was also calculated from the optical spectroscopy curve, which is close to that obtained from AFM observation. The gas-sensing properties of the multi-layers for alcohols with different chain lengths were measured at room temperature. The thin films exhibited high sensitivity and rapid response-recovery characteristics to these gases. The film can detect methanol, ethanol and propyl alcohol vapor as low concentration as 1, 10, and 0.5 ppm, respectively. (C) 2004 Elsevier B.V. All rights reserved.