A chemical sensor based on amicromechanical cantilever array for the identification of gases and vapors

Abstract

We have built and operated a novel setup for the characterization and identification of gases or vapors based on sequential position readout via a beam-deflection technique from a microfabricated array of eight cantilever-type sensors. Each of the cantilevers can be coated on one side with a different sensor material to detect specific chemical interactions. We demonstrate that disturbances from vibrations and turbulent gas flow can be effectively removed in array sensors by taking difference signals with reference cantilevers. For example, H2 can be detected by its adsorption on a Pt-coated sensor because a change in surface stress causes a static bending of the sensor. The diffusion of various alcohols into polymethylmethacrylate induces resonance frequency shifts in a dynamicmeasuring mode and bending in the static mode, which allows one to distinguish between the various alcohols. © 1998 Springer-Verlag.