Metal Oxide Thin Films for Chemical and UV Sensors

Highly sensitive and fast responding Titanium Dioxide (TiO2) nano sensors are developed for CO gas and other materials such as methanol and methane. Nano-porous TiO2 thin films are prepared from a colloidal solution of TiO2 nano particles (P-25) in ethanol by spray pyrolysis deposition (SPD) technique. Initially the TiO2 films are grown at 60 0C and after the deposition, backed in an oven at 65 0C overnight and then annealed at 450 0C for one hour to get anatase phase. The surface morphology and structural properties of the films are studied using SEM and XRD. For sensor applications, two gold contacts separated by 0.25 mm are made on quartz substrate. A sensing and testing system has been developed based on change in the resistance of the TiO2 film. CO gas (2% in Air) through mass flow controller is used for repeated five minutes cycles of air and CO at different temperatures in the range of 200 0C to 350 0C. Response and sensitivity of the sensor has been studied. Same apparatus and sensor is also used to detect UV, methane and methanol respectively.