Gas sensing response of NiO nanoparticle films made by reactive gas deposition

Nanocrystalline films comprised of NiO particles were prepared by advanced reactive gas evaporation and were investigated for gas sensing applications, specifically for detecting reducing (H2S) and oxidizing (NO2) species. The films were studied in as-deposited state and after annealing at temperatures up to 400 °C, and the sensors were operated from room temperature to 325 °C. The optimal operating temperature was in the 150–162 °C range for H2S and in the 100–125 °C range for NO2. We believe that this is the first report of high-sensitivity detection of H2S with NiO-based sensors, as well as the first proof that such sensors can work at room temperature.