On the correlation between morphology and gas sensing properties of RGTO SnO2 thin films

In this paper, we present the results of studies on optimalisation of morphology of the SnO2 thin films grown by RGTO technique for application as gas sensor structures. The Sn thin films were grown on Si(111) wafer and Al2O3 ceramic plate heated in the range 235-295 °C and subsequently oxidized in dry oxygen atmosphere at high temperature, up to 700 °C. Our studies confirmed that the highest surface coverage of Sn droplets can be reached for the substrate temperature of about 265 °C leading to the highest surface-to-volume ratio of SnO2 thin films. It was in a good correlation to the optimal gas sensor response and sensor sensitivity of RGTO SnO2 thin films to nitrogen dioxide NO2.