Room temperature NO2-sensing properties of porous silicon/tungsten oxide nanorods composite

摘要

One-dimensional single crystalline WO3 nanorods have been successfully synthesized onto the porous silicon substrates by a seed-induced hydrothermal method. The controlled morphology of porous silicon/tungsten oxide nanorods composite was obtained by using oxalic acid as an organic inducer. The reaction was carried out at 180 degrees C for 2 h. The influence of oxalic acid (pH value) on the morphology of porous silicon/tungsten oxide nanorods composite was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The NO2-sensing properties of the sensor based on porous silicon/tungsten oxide nanorods composite were investigated at different temperatures ranging from room temperature (similar to 25 degrees C) to 300 degrees C. At room temperature, the sensor behaved as a typical p-type semiconductor and exhibited high gas response, good repeatability and excellent selectivity characteristics toward NO2 gas due to its high specific surface area, special structure, and large amounts of oxygen vacancies. (C) 2015 Elsevier B.V. All rights reserved.