Integration of porous silicon chips in an electronic artificial nose

Porous silicon (PSi) films displaying both photoluminescence (PL) and interference fringes were etched, stabilized by anodic oxidation, and mounted in a specially designed chamber connected to the gas flow system of an electronic artificial nose (FOX 3000 from Alpha MOS). The changes in reflectivity and PL spectra of experimental PSi chips were recorded during the injection of analyte, and compared to the response of commercial chemiresistive metal oxide sensors. A series of solvent vapors, ethyl esters, and perfumes were investigated and discrimination indices (DI) obtained with PSi sensors have been found to be as good as those obtained with metal oxide sensors. The PL and reflectivity signals from PSi chips are reversible and reproducible. Moreover, the recovery to baseline for the PSi chips takes 30 s while the metal oxide sensors under similar conditions require 15 min.