In this article a new method is demonstrated for improving gas sensor characteristics. An electronic sparker is included in a semiconducting SnO2 thin-film sensor system for cracking the gas molecules to be detected. The distance between the electrodes is 0.2 mm, which conforms to a 1-1.8 kV breakdown voltage at 0.1-0.5 mA coming from a current-limited power supply. A good correlation exists between the characteristics of this composite sensor system and the structure of detectable gas molecules. For small gas concentrations (below 1% for CH4, 0.01% for normal C6H14 and C4H10) the sensor resistivity increases due to the spark discharge, as well as in clean air. At moderate and high concentrations of hydrocarbons, the spark discharge improves the sensitivity, depending on the structure and the hydrogen content of the molecule. Chlorine and other halogen-containing gases and solvent vapours, such as CCl4, CHCl3, CH2Cl2 and CF2Cl2, also yield a higher resistivity after sparking, even at high concentrations (5% or more).
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Metals and Alloys
- Electrical and Electronic Engineering
- Materials Chemistry