Single crystal ZnO nanowires as optical and conductometric chemical sensor

ZnO nanowires were deposited using the vapour phase technique. The nanowires cover the substrate and appear uniform in morphology with lengths of up to several micrometres and uniform lateral size of the order of tenths of a nanometre. The electrical and optical properties of ZnO nanowires have been characterized in the presence of nitrogen oxide. Electrical measurements highlight a remarkable response even at low operating temperatures, with detection limits lower than 200 ppb and an optimal operating temperature of 100 degrees C, while the ZnO nanowire photoluminescence is reversibly quenched by the introduction of a few ppm of NO2 even at room temperature.