Nanostructures and porous silicon: activity at interfaces in sensors and photocatalytic reactors

Nanopore covered microporous porous silicon (PS) interfaces have been formed to provide an active scaffolding for the creation of sensor and microreactor configurations. Rapidly responding (<= 2s), reversible, and sensitive (<= 2 ppm), PS gas sensors, operating at room temperature, and based on a uniquely formed highly efficient electrical contract to the nanopore covered microporous array, are modified by introducing active nanoparticles to establish gas selectivity. In a complementary manner, active sites can be introduced for the purpose of forming a nanostructure based microreactor. Pulsing techniques and FFT analysis allow the gas response of the sensors to be measured, without saturation, and filtered on a drifting baseline to eliminate false positives and the effects of external noise. TiO2-xNx visible light absorbing photocatalysts are introduced to quartz surfaces and to the PS structure for the purpose of creating a microreactor and subsequently to form the preconditioner for a solar pumped sensor. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.