Vertically aligned silicon nanowires with rough surface and its NO2 sensing properties
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Vertically aligned array of silicon nanowires (SiNWs) with rough surface was demonstrated to be a promising material for high performance gas sensor applications. A two-step etching process, i.e. metal-induced chemical etching followed by the back-etching of KOH was developed to prepare the rough SiNWs array. The roughness of SiNWs effectively increases the active surface area as evidence that the measured BET specific area is ten times larger than that of the smooth nanowires without KOH etching. Meanwhile, the nanowire diameter and distribution density are also decrease due to KOH etching. The high active surface area and loose configuration of the rough SiNWs array are favorable for gas adsorption and rapid gas diffusion. As a result, the sensor based on the rough SiNWs array exhibits high response, good stability and satisfying response–recovery characteristics in detection of NO2 in ppb–ppm level at room temperature.
KeywordsSilicon Nanowires SiNWs Array Nanowire Diameter High Active Surface Area Satisfying Response
This work was financially supported by the National Natural Science Foundation of China (Nos. 61574100, 61274074, 61271070).