Detection of pollutant gases using electrostatic sprayed indium oxide and tin-doped indium oxide

The aim of this paper is to present the gas sensing performance of In 2O 3 and Sn-doped In 2O 3 films prepared by a novel technique, i.e., Electrostatic Spray Deposition technique. The morphology and the microstructure studies reveal that the films are porous comprising grains in the nanometer range and crystallizing in the cubic structure. The present films prove to be sensitive to low H 2S concentrations (1–10 ppm) at low operating temperature (200 °C). Undoped films present a very high sensitivity to H 2S, compared with doped films, and a negligible response to NO 2 and SO 2. Sn dopant introduced in In 2O 3 causes a great sensitivity decrease in H 2S response, and, on the contrary, a slight increase in NO 2 and SO 2 response.