The semiconductor characteristics of these nanowires have been carefully verified by Hall measurement and using a single nanowire FET device. The nanowires have been shown to exhibit p-type conductance behaviour such that the conductance of the as-prepared sensor rapidly decreases as the sensor is exposed to ethanol gas. Once the ethanol gas is removed, the conductance of the sensor recovers to its original level. A rapid response time of ~8 seconds was obtained.

Performance upgrade

Although there have been many reports of n-type ethanol sensors made from SnO2 nanostructures, SnO2 nanowires doped with low valence cations of Sb+3 that exhibit p-type sensing behaviour for detecting ethanol gas at low temperature have rarely been investigated. These newly developed p-type sensors overcome the traditional concepts of common n-type sensors. Moreover, the p-type sensor exhibits better temperature performance compared with an n-type sensor.

The major challenge is how to optimize the sensitivity and recovery time by either controlling the dopant concentration or materials synthesis, both of which are key variable conditions.

More information can be found in the journal Nanotechnology.