Porous Silicon Gas Sensing

In this chapter, the state of the art on porous silicon gas sensors , both electrical and optical, is reviewed by paying special emphasis on the advancement of gas sensor architectures that has occurred over the two last decades, as well as on the different functionalization approaches implemented in and chemical species sensed with such architectures. Ten main architectures, five for the electrical domain (capacitor, Schottky-like diode, resistor, FET-like transistor, and junction-like diode) and five for the optical domain (single layer, waveguide, Bragg mirror, resonant cavity, and rugate filter), have been proposed so far for improving gas sensor features. Several functionalization schemes have been integrated in such architectures to improve sensor performance, and more than 50 different chemical species have been sensed using porous silicon gas sensors. The latest trends on multiparametric sensing on single devices as well as on multisensor integration in a single chip, for both optical and electrical domains, are also discussed.