Parts per Billion-Level H2S Detection at Room Temperature Based on Self-Assembled In2O3 Nanoparticles

Homogenous In2O3 nanoparticles (NPs) with diameters in the range of 6-10 lint were synthesized via it chemical Solution method, and nanoparticles were assembled on Si substrate for H2S detection. The sensor demonstrates ultrahigh sensitivity to H2S to part per billion (ppb) levels at room temperature. Different sensor parameters were then investigated in terms of electrode gap, In2O3 NP film thickness, and Surface modification by noble metals. It was found that sensitivity was slightly improved by reducing the electrode gap or increasing NP film thickness. However, sensitivity was dramatically enhanced (from 20 ppm to 20 ppb) after surface modification with 0.3 nm Au deposition. In addition, the sensor also shows a certain selective detection to H2S in comparison with other gases such as CO and NO2.