A highly sensitive and room temperature ethanol gas sensor based on spray deposited Sb doped SnO₂ thin films

A room temperature ethanol gas sensor designed using antimony (Sb)-doped tin dioxide (SnO2, ATO) nanostructure thin films was prepared via the chemical spray pyrolysis method as a function of Sb concentration (0, 2, 4, 6, and 8 wt%) at 420 degrees C. Structural, surface, optical, electrical, and temperature-dependent resistance studies were carried out using XRD, FESEM, UV-visible, and four-probe electrical resistivity techniques. Structural and surface microstructure analysis of the films confirms the nanostructure formation. Optical band gap and electrical resistivity studies demonstrate that the n-type conducting behavior of the films increased upon Sb doping. Temperature-dependent sheet resistance analysis confirms that ATO thin films exhibit maximum resistance stability up to 350 degrees C. The sensitivity of the fabricated ATO sensors strongly depends on the surface structure of the films, and the adsorbed gas molecules cause a change in the resistance of the films. A significant improvement was observed in the recovery and response times of the sensors as a function of Sb-doping content and ethanol exposure level. The maximum ethanol response achieved in the 6 wt% Sb-doped SnO2 (ATO6) film was 842% for 50 ppm with a response and recovery time of 259/214 s, respectively. Hence, the ATO6 film exhibited a better sensing performance towards ethanol sensing applications.