Hydrogen sensitive gas sensor based on porous silicon/TiO2-x structure

Porous silicon (PS) layer was formed by electrochemical anodization on a p-type Si surface. Thereafter, n-type TiO2-x thin film was deposited onto the PS surface by electron-beam evaporation. Pt catalytic layer and Au electrical contacts for further measurements were deposited onto the PS/TiO2-x structure by ion-beam sputtering. Current-voltage characteristic, sensitivity to different concentration of hydrogen and resistance change of obtained structures versus time were examined. Results of measurements have shown that the current-voltage characteristics of structures are similar to that of diode. High sensitivity to hydrogen of obtained structures was also detected. Note that all measurements were carried out at room temperature. © 2007 Elsevier B.V. All rights reserved.