Oxide nanobelts as conductometric gas sensors

Semiconducting oxide nanobelts have been obtained by vapor phase deposition. In this work we present the results obtained using tin oxide nanobelts as conductometric gas sensors. Electrical characterization showed that the nanobelts were sensitive to oxygen and environmental polluting species such as CO as well as ethanol for breath analyzers and food control applications. The sensor response, defined as the relative variation in conductance or resistance due to the introduction of the gas, is 200% for 30 ppm of CO at 623 K and 2500% for 10 ppm of ethanol at 623 K. We have studied the variation of the response as a function of the density of the nanobelts. The results demonstrate the potential of fabricating nanosize sensors using the integrity of a single nanobelt with sensitivity at the level of a few ppb and the necessity to control nanobelts density to optimize the sensing performances.