Nanostructured thin films of Ba doped In2O3 sensors for monitoring trace levels of NOx

In this paper, the results of barium oxide doped indium oxide films as sensor material for monitoring ppm levels of NO_x (a mixture of NO and NO₂) in ambient have been presented. The parameters for obtaining nanostructured and textured thin films of Ba doped In₂O₃ using pulsed laser deposition (PLD) technique have been optimized. These films are found capable of sensing down to 0.5 ppm NO_x concentration in air. The optimum operating temperature of the sensor is found to be 300degC. Response and retrace times are typically 60 and 300 seconds respectively. This sensor did not show significant response to hydrogen and petroleum gas up to 5000 ppm each.