Robust gas detection at sub ppm concentrations
2011 (English)In: Sensors and actuators. B, Chemical, ISSN 0925-4005, Vol. 160, no 1, 571-579 p.Article in journal (Refereed) Published
Gas sensors often suffer from signal drift and long response and recovery times, giving rise to problems to evaluate the steady state gas response. It is shown that these problems can be reduced by modulating the test gas concentration and utilizing the change in the slope of the sensor signal as the sensor response feature. The case of low hydrogen concentration detection is studied using a light pulse technique and a PdPt-MIS field-effect device. For the difference in slope method it was possible to reduce the measurement time from hours in the steady state measurements to 1 + 1 min (test gas + reference gas exposure time) and still achieve a detection limit of about 40 ppb for a step change in hydrogen concentration. Such measurements could be made in spite of a drifting baseline caused, e.g. by previous hydrogen exposures. A theoretical model of how a step change in the hydrogen partial pressure affects the difference in slope is given. The model also predicts a non-reactive hydrogen sticking probability (i.e. the probability that an incoming hydrogen molecule from the gas phase will contribute to the response) of about 1 x 10(-8) at 100 ppb H(2), which is about 2 orders of magnitude lower than the reactive sticking coefficient. (C) 2011 Elsevier B.V. All rights reserved.
Place, publisher, year, edition, pages
Elsevier , 2011. Vol. 160, no 1, 571-579 p.
Gas sensor, Hydrogen, Field-effect device, Scanning light pulse technique, Modulation, Sub ppm detection
National CategoryEngineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-74861DOI: 10.1016/j.snb.2011.08.031ISI: 000298768100081OAI: oai:DiVA.org:liu-74861DiVA: diva2:496535
Funding Agencies|Swedish Research Council||Network of Excellence, GOSPEL, General Olfaction and Sensing Projects on a European Level, EU||2012-02-102012-02-102015-03-24