Enhanced gas-sensing performance of SnO2/Nb2O5 hybrid nanowires

Abstract

Semiconductor tin oxide (SnO₂) is acknowledged to be one of the semiconductor oxides with most potential for utilization as nitrogen dioxide (NO₂)-sensor materials. However, the challenge to improve the gas sensitivity still remains, and this limits the full realization of the SnO₂ sensor potential. In this paper, enhanced gas sensitivity obtained by the formation of a SnO₂/niobium pentoxide (Nb₂O₅) hybrid structure is reported. As the NO₂ concentration is lower to 3 ppm, the measured resistance in the SnO₂/Nb₂O₅-based sensor is still 2.5 times larger than that in a pristine SnO₂-based sensor. With an increase in the NO₂ concentration, the response time of the SnO₂/Nb₂O₅-based sensor decreases sharply whereas the pristine SnO₂-based sensor response time increases. The enhanced performance is attributed to the presence of more oxygen vacancies and a higher specific surface area in the hybrid structure induced by the introduction of Nb₂O₅. These results provide some general guidelines for the selection of compositions to enhance the sensor performance.