SnO2 nanowires have been recently employed in the “gas-sensors” field and excellent results of conductometric and optical tests on SnO2 nanowires-based gas sensors have been reported.
However, the mechanism that controls the gas-sensing effect in metal oxides nanowires is not fully understood yet. Here the authors present the first results of an in-depth study about the influence of post growth treatments on the physical and gas sensing properties of SnO2 nanowires.
In particular, SnO2 nanowires grown by a vapour transport technique were annealed in a oxygen-rich atmosphere and then characterized by different techniques to assess the influence of the treatment on the nanowires properties.
The annealing in oxygen atmosphere is shown to strongly affect the PL and CL spectra, the electrical resistivity as well as the gas sensing properties of the nanowires. The obtained results are consistent with a reduction of the oxygen vacancies concentration induced by the O2 treatment and seem to confirm the role of these defects in affecting the gas response of SnO2 nanowires-based sensors.