Porous Si/SnO2 nanowires heterostructures for H2S gas sensing

In this work, a low-temperature (100 degrees C) gas sensor based on heterojunctions of porous Si and SnO2 nanowires (NWs) is presented. Porous Si was obtained from p-Si wafers by electrochemical etching, and SnO2 NWs were fabricated by a vapor-liquid-solid route. Different characterization techniques were used to verify the formation of porous Si/SnO2 NW heterojunctions. H2S gas sensing results showed enhanced gas sensing performance of the porous Si/SnO2 NW sensor in comparison with that of a porous Si sensor. The reasons for such enhancement are discussed in detail. This study demonstrates the promising effects of SnO2 NWs in combination with porous Si to realize low-temperature H2S gas sensors that are highly compatible with existing Si processing technology.