Room temperature gas sensing properties of porous silicon/V2O5 nanorods composite

Here we prepare a composite of porous silicon (PS)/V2O5 nanorods synthesized by a heating process of pure vanadium film on PS. Vanadium films were deposited on PS by DC magnetron sputtering, and then long striped V2O5 nanorods were synthesized with subsequent annealing process in air. Numerous analytical techniques, such as field emission scanning electron microscope (FESEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM), have been employed to characterize their feature. The as-prepared composite structure of PS/V2O5 nanorods shows favorable microstructure features for gas sensing application. The gas sensing properties of PS/V2O5 nanorods sensors were investigated at 25 °C up to 250 °C toward NO2 gas of 0.25-3 ppm, and ethanol over concentration of 50-250 ppm. The results indicated that the PS/V2O5 structure exhibits perfect reversibility, high response value and good selectivity to NO2 at room temperature (25 °C). In addition, we propose a qualitative explanation for the low operating temperature (25 °C) of the composite structure. These results are significant from the standpoint of applications requiring room temperature gas sensing.