Effect of light activation on chemical gas sensors based on aligned nanowires

We investigated the effect of light activation on the gas sensors based on aligned nanowires (NWs). Due to almost monocrystalline perfection, NWs exhibit excellent chemical and thermal stability that makes them superior to polycrystalline thin-film sensors. Nanowires were aligned in two different ways: using Langmuir-Blodgett technique on a chip with electrodes being two microns apart, and using hydrothermal growth procedure to obtain inter-crossed nanowires. Our objective was to fabricate multiple aligned nanowire sensors that could mimic the advantages of a single NW sensors, but benefiting from a macroscopic alignment procedure that avoid the use of lithography for making contacts on a single nanowire. In the present study, we investigated the effects of illumination wavelength (sub and supra band-gap) on the sensing capabilities of the developed structures at room temperature. Light activated devices were found effective for NO
₂
sensing, while no interference to ethanol and relative humidity was observed.