Nanostructured tin oxide films: Physical synthesis, characterization, and gas sensing properties

Nanostructured tin oxide (SnO₂) films are synthesized using physical method i.e. thermal evaporation and are further characterized with X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy measurement techniques for confirming its structure and morphology. The chemiresistive properties of SnO₂ films are studied towards different oxidizing and reducing gases where these films have demonstrated considerable selectivity towards oxidizing nitrogen dioxide (NO₂) gas with a maximum response of 403% to 100ppm @200°C, and fast response and recovery times of 4s and 210s, respectively, than other test gases. In addition, SnO₂ films are enabling to detect as low as 1ppm NO₂ gas concentration @200°C with 23% response enhancement. Chemiresistive performances of SnO₂ films are carried out in the range of 1-100ppm and reported. Finally, plausible adsorption and desorption reaction mechanism of NO₂ gas molecules with SnO₂ film surface has been thoroughly discussed by means of an impedance spectroscopy analysis.