The gas sensing, electrical and chemical properties of a novel toxic gas sensor structure based on n-InP epitaxial layers have been investigated. The gas sensing properties were investigated under extremely low concentration of toxic gas flow, nitrogen dioxide, in dry pure air. Responses, resistance changes ∃R, towards NO2 of the structures with different active InP layer thickness were compared. The influence of the surface states at InP surface on the initial resistance of the sensor structure was shown from numerical simulations. Furthermore, the changes of InP surface chemical properties due to gas exposition were stud-ied using the X-ray photoelectron spectroscopy (XPS).
