(Bio)Chemical Sensors • A (bio)chemical sensor is a device which is capable of converting a chemical (or biological) quantity into an electrical signal. • Interaction of a chemical species (X) with the sensing material (M) may often be described as • The selectivity of a chemical sensor depends on the nature of the reaction mechanism.
Chemoresistors • The simplest type of chemical sensors is the chemoresistor in which a change in the electrical conductivity of a chemically-sensitive layer is measured. A schematic structure of a chemoresistive gas sensor
Chemocapacitors • It is possible to measure the gas sensitivity of the dielectric constant of a film using a parallel-electrodes arrangement. Structure Typical response
Chemodiodes Structure Response of an organic chemodiode in sensing Nox and NH3
Chemotransistors • A MOSFET hydrogen sensor exhibits a shift in threshold voltage, DVT. Structure of Pd-gate gas sensitive MOSFET Response of a chemotransistor