FABRICATION OF CARBON-TETRACHLORIDE GAS SENSORS USING INDIUM TIN OXIDE THIN-FILMS

Indium tin oxide (ITO) polycrystalline thin films grown on alumina substrates by the thermal evaporation technique are used for fabricating gas sensors to detect carbon tetrachloride (CCl4). The electrical conductance of the sensors appears to increase and decrease on exposure to gaseous CCl4, depending on the operating temperature. The thin-film gas sensors with a thickness of about 100 nm show a maximum sensitivity when operated at 448 K for various concentrations of CCl4. A tentative mechanism is proposed for the role of CCl4 gas in increasing and decreasing the conductance of ITO thin-film gas sensors with changes of operating temperature.