Effect of rf power on the structural properties of indium tin oxide thin film prepared for application in hydrogen gas sensor

Indium tin oxide films were grown on glass substrate by rf magnetron sputtering at 648 K. Influence of rf power on structural properties of the ITO films was studied. XRD measurements showed (222) preferred orientation under the optimized deposition conditions. The surface morphology of ITO films analyzed by scanning electron microscope appears to be uniform over the entire surface area, the film exhibited dense layers with fine grains. Finally, ITO sensor device was fabricated and the sensing properties of the device towards hydrogen gas were investigated. The variation in sensitivity of the ITO sensor with operating temperature and with concentration of hydrogen gas was studied. The maximum response was found to be 1.6 at 400 K, for 1,000 ppm of hydrogen gas, and the response of the sensor was found to decrease with increase in concentration of H₂ gas.