High sensitivity NO2 sensor based on CuO/p-porous silicon heterojunction at room temperature

Abstract A new type NO 2 gas sensor constructed with CuO/p-porous silicon(PS) heterojunction was prepared in this paper. The sensor was fabricated by sputtering Cu films on PS substrate and then heating in the furnace tube. The morphology and crystallographic structrue of sensors were investigated by using field emission scanning electron microscope (FESEM) and X-ray diffractometer (XRD). The sensing properties of the sensors were investigated from 25 °C to 100 °C toward 125 ppb–1000 ppb NO 2 . The sensor showed high sensitivity and good selectivity of NO 2 at room temperature(25 °C). The sensing mechanism was also discussed in the paper, in which the effect of heterojunction of CuO and PS was introduced.