The properties of gas-sensitive semiconductor devices with catalytic metal gates are reviewed, with emphasis on field-effect structures sensitive to hydrogen-containing molecules like H2, NH3, H2S, alcohols, ethylene etc.
A brief review of some of the developed device structures are given. The principles of hydrogen sensors with Pd gates are described in some detail. Ammonia-sensitive field-effect devices with thin catalytic metal gates are discussed. Applications of gas-sensitive field-effect devices for studies of catalytic reactions together with electron spectroscopy in UHV systems, for medical diagnosis, in leak detectors and as biosensors are reviewed.