Catalytic Pd–TiO 2 thin film based fire detector to operate at room temperature

Abstract

Attempts made in past to detect target gases using semiconductor structure required high operational temperature. Whereas, in the present study, our research group could detect CO 2 gas at room temperature without using vacuum condition. For this purpose, a micro-fabricated device was made with simple MIS structure having Pd/TiO 2/SiO 2/Si-wafer/Al layers. The sensing performance of device was dependant on Pd–TiO 2 catalytic sensing layer quality because the role of TiO 2 layer was to reduce work function barrier between palladium and SiO 2 layer. The TiO 2 layer prepared by sintering at 500 °C or above showed anatase phase in XRD analysis. By using this device we could detect between 2.5% and 12.5% CO 2.