Investigations of hydrogen sensors made of porous silicon

Porous silicon layer was formed by electrochemical anodization on n- and p-type silicon surface. Thereafter n-type TiO1.98 and ZnO?Al? thin films were deposited onto porous silicon surface by electron-beam evaporation and magnetron sputtering, respectively. A Pt catalytic layer and Au electrical contacts for further electrical measurements were deposited by ion-beam sputtering. Changes in sensitivity versus time of obtained structures were examined for different concentrations of hydrogen gas and propane-butane mixture. High sensitivity and selectivity to hydrogen gas was detected. All measurements were carried out at 40 °C. © 2008 Elsevier B.V. All rights reserved.