A4.2 - Detection of short trace gas pulses
- AMA Conferences 2017
2017-05-30 - 2017-06-01
- Proceedings Sensor 2017
- A4 - Gas Sensors I
- T. Baur, A. Schütze, T. Sauerwald - Saarland University, Saarbrücken (Germany)
- 87 - 91
A novel method for detection of short gas pulses at very low concentrations is presented. The approach is based on a special temperature modulation technique leading to the differential measurement of surface reduction (DSR) of a metal oxide semiconductor (MOS) gas sensor. For this method, the sensor surface is oxidized at high temperature (e.g. 400 °C). An abrupt step in temperature to e.g. 100 °C results in a nonequilibrium state with a strong excess of negative surface charges. Reactions of these surface charges with reducing gas are prevailing and lead to a very high sensitivity. Applying the method to a commercial SnO2 sensor, gas pulses down to 1 ppb s (ppb times seconds) can be detected as demonstrated for ethanol.