Studies of the detection mechanism of FET gas sensors

Research Project, 2009 – 2011

This project is focused on the understanding of the detection mechanism of chemical gas sensors, with special emphasis on field effect transistor (FET) sensors with catalytic metal gates for detection of H2, NH3, CO and NOx. This type of chemical sensors has high potential to be used in several applications including NH3 and NOx sensors for control of selective catalytic reduction of nitrogen oxides by NH3 in diesel and lean-burn exhausts, and sensors for control of combustion processes. The overall goal is to obtain knowledge on the molecular level of the detection mechanism of FET gas sensors, which provides a strong tool for tailor-made selective and long term stable gas sensors. Special attention will be paid on the correlation between surface adsorbates and sensor response for hydrogen-containing gases, like H2 and NH3, and non-hydrogen containing compounds, like NO and CO. By using in situ infrared spectroscopy combined with sensor response measurements and supported by first principles calculations we will identify the active sites on the sensor surface, and the adsorbed species involved during the detection of these gases. The project will also result in knowledge, which most likely will be useful also in the area of environmental catalysis.