Selectivity enhancement of a WO 3/TiO 2 gas sensor by the use of a four-point electrode structure

• Published in: Sensors and actuators. B, Chemical Vol. 93; no. 1; pp. 503 - 508
• Main Authors: Gerlich, M., Kornely, S., Fleischer, M., Meixner, H., Kassing, R.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2003
• Subjects: Air quality sensor; Four-point structure; Selectivity enhancement; Titanium oxide; Tungsten oxide; Tungsten oxide; Four-point structure; Air quality sensor; Selectivity enhancement; Titanium oxide
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/S0925-4005(03)00187-4

A new electrode structure with two additional middle-electrodes running in-between the interdigitated electrodes, is presented. With this structure, the voltage drops at these middle-electrodes are measured as well as the conductivity of a screen printed n-type WO 3/TiO 2 mixed oxide layer. The gas-sensing properties to NO x , CH x and CO are determined at 300 °C. It is shown that with this four-point structure, different sensor regions, namely the pure semiconducting layer and the interface electrode/semiconductor, can be separated and different gas-sensing properties can be determined for this regions. Additionally, by evaluating the signals at the middle-electrodes, single gases in gas mixtures can be detected and discriminated.