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.