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We prepared macro-porous silicon(MPS) by electrochemical corrosion in a double-tank cell on the surface of single-crystalline P-type silicon.Then,nano-WO_3 films were deposited on MPS layers by DC facing target reactive magnetron sputtering.The morphologies of the MPS and WO_3/MPS samples were investigated by using a field emission scanning electron microscope.The crystallization of WO_3 and the valence of the W in the WO_3/MPS sample were characterized by X-ray diffraction and X-ray photoelectron spectroscopy,respectively. The gas sensing properties of MPS and WO_3/MPS gas sensors were thoroughly measured at room temperature. It can be concluded that:the WO_3/MPS gas sensor shows the gas sensing properties of a P-type semiconductor gas sensor.The WO_3/MPS gas sensor exhibits good recovery characteristics and repeatability to 1 ppm NO_2.The addition of WO_3 can enhance the sensitivity of MPS to NO_2.The long-term stability of a WO_3/MPS gas sensor is better than that of an MPS gas sensor.The sensitivity of the WO_3/MPS gas sensor to NO_2 is higher than that to NH_3 and C_2H_5OH.The selectivity of the MPS to NO_2 is modified by deposited nano-WO_3 film.
We prepared macro-porous silicon (MPS) by electrochemical corrosion in a double-tank cell on the surface of single-crystalline P-type silicon. Chen, nano-WO 3 films were deposited on MPS layers by DC facing target reactive magnetron sputtering. morphologies of the MPS and WO_3 / MPS samples were investigated by using a field emission scanning electron microscope. The crystallization of WO_3 and the valence of the W in the WO_3 / MPS sample were characterized by X-ray diffraction and X-ray photoelectron spectroscopy, respectively. The gas sensing properties of MPS and WO_3 / MPS gas sensors were thoroughly measured at room temperature. It can be concluded that: the WO_3 / MPS gas sensor shows the gas sensing properties of a P-type semiconductor gas sensor. MPS gas sensor exhibits good recovery characteristics and repeatability to 1 ppm NO 2. The addition of WO 3 can enhance the sensitivity of MPS to NO 2. The long-term stability of a WO 3 / MPS gas sensor is better than that of an MPS gas sens or the sensitivity of the WO_3 / MPS gas sensor to NO_2 is higher than that to NH_3 and C_2H_5OH. The selectivity of the MPS to NO_2 is modified by deposited nano-WO_3 film.