Synthesis and Characterize of Metal oxide Nano-Structure for Sensors Application

Abstract

In this research are separated into two parts. In first part, we report the fabrication of WO3 by GLAD technique with DC magnetron sputtering system, while the substrate was tilted at 0 to 85 and study of crystal structure, morphology and tested toward ethanol gas sensing. Characterization results showed that the as-deposited structure exhibited amorphous phase and crystallinity was improved after annealing at 300C. From morphological characterization, WO3 thin films prepared with the substrate tilted at 85 comprise isolated good columnar nanorods structure. The gas-sensing results indicated that WO3 thin films exhibited p-type conductivity with increased resistance when exposed to ethanol, which was reducing gas. The ethanol sensing of WO3 thin films was increased with the substrate tilted from 0 to 85. In addition, WO3 thin films were capable of detecting ethanol gas at concentrations lower than 5 ppm at operating temperature 200 °C. In the second part, we report the fabrication of SnO2 by GLAD technique with DC magnetron sputtering system, while the substrate was tilted at 87 and annealed at 300C and 400C. Then, study of crystal structure, morphology and tested toward NO2 gas. Characterization results showed that the structure of SnO2 thin films exhibited tetragonal phase and crystallinity was improved after annealing at 300 and 400C. From morphological characterization, SnO2 thin films prepared with the substrate tilted at 87 comprise isolated columnar nanorod structures. The gas-sensing results indicated that nanorod structures provides significant improvement on NO2 response at operating temperature 60C to 250C. As a result, SnO2 thin films exhibited n-type conductivity with increased resistance when exposed to NO2, which was oxidize gas. SnO2 nanorods exhibited a high NO2 response at the optimal operating temperature of 150C. In addition, SnO2 nanorods exhibit relatively fair response time of 5.9 min and recovery time of 2.6 min.