Novel Concept for the Formation of Sensitive, Selective, Rapidly Responding Conductometric Sensors

Rapidly responding, reversible, sensitive, and selective porous silicon gas sensors, operating at room temperature, are formed with a highly efficient electrical contact to a nanopore covered microporous array. Variable surface sensitivities are facilitated for a variety of gases, based on a complementary concept to that of strong and weak acid-base (HSAB) interactions and commensurate with a basis in physisorption. A range of highly selective surface deposits have been placed on nanopore covered porous silicon micropores with the application of nanostructured metals, metal oxides, and nanoparticle catalytic coatings, providing for notably higher sensitivities and selectivity. Single nanostructure depositions, which include electroless gold, tin, copper, and nickel, as well as nano-alumina, magnesia, and titania provide for the detection of gases including NO, NO2, CO, NH3, PH3, SO2, H2S, HCl, and toluene in an array-based format at the sub-ppm level