Very sensitive porous silicon NO2 sensor

We report a nitrogen dioxide sensor suitable for environmental control, based on the change in conductivity of a single meso-porous silicon (PS) layer with about 80% porosity. We present the characterization of the sensor in the presence of low concentrations of NO2 in dry air and study the influence of humidity on sensor behaviour. The sensor shows a sensitivity to 12 ppb of NO2 in dry air and a good response to 50 ppb in humid air.