Influence of surface parameters and doping on the sensitivity and on the response times of tin oxide resistive sensors

Abstract A systematic analysis of the correlations between preparation conditions and physical properties has been carried out on tin oxide films, deposited onto high purity Al 2 O 3 substrates using a variant of the chemical vapour deposition (CVD) technique, with the aim of optimizing the gas-sensing properties of these devices. It has been demonstrated that the nature of the precursor used for tin oxide preparation is of importance for the effective gas performance of the sensor; tin oxide from organometallic precursors is the most suitable active layer for H 2 detection and also results in a very fast response time. Sb doping is a very effective way of extending the sensitivity to the largest hydrogen partial pressures. The experimental determination of the surface trap level relative to the chemisorbed oxygen has been performed using a novel fitting procedure of the conductivity transients.