Fast response time alcohol gas sensor using nanocrystalline F-doped SnO2 films derived via sola€“gel method

摘要

Pure and fluorine-modified tin oxide (SnO₂) thin films (250a€“300 nm) were uniformly deposited on corning glass substrate using sola€“gel technique to fabricate SnO₂-based resistive sensors for ethanol detection. The characteristic properties of the multicoatings have been investigated, including their electrical conductivity and optical transparency in visible IR range. Pure SnO₂ films exhibited a visible transmission of 90% compared with Fdoped films (80% for low doping and 60% for high doping). F-doped SnO₂ films exhibited lower resistivity (0.12 ?— 10-4e??o cm) compared with the pure (14.16 ?— 10-4e??o cm) one. X-ray diffraction and scanning electron microscopy techniques were used to analyse the structure and surface morphology of the prepared films. Resistance change was studied at different temperatures (523a€“623 K) with metallic contacts of silver in air and in presence of different ethanol vapour concentrations. Comparative gas-sensing results revealed that the prepared F-doped SnO₂ sensor exhibited the lowest response and recovery times of 10 and 13 s, respectively whereas that of pure SnO₂ gas sensor, 32 and 65 s, respectively. The maximum sensitivities of both gas sensors were obtained at 623 K.