Microfabricated chemical sensors

This paper describes the basic structures employed in costructing chemical sensors. In particular four kinds of devices are considered and discussed in some detail: metal-oxide-semiconductor capacitors and field effect transistors which are sensitive to electronic charge variations, piezoelectric devices which are sensitive to mass variations, pyroelectric materials which show sensitivity to heat variations and optical devices where optical parameters are influenced by chemical species. Examples of hydrogen sensors constructed by these different detection methods are illustrated and discussed. Furthermore immunosenducers are also taken into consideration as a growing and promising subject for advanced research in chemical sensors. © 1988.