Study on hydrogen reactivity with surface chemical species of nanocrystalline porous silicon

The nanocrystalline porous silicon was prepared by the electrochemical etching of Si in a HF solution. A semi-transparent palladium layer was thermally deposited on its surface. Micro-Raman spectra were recorded in air and in the presence of hydrogen. Different SiHX stretching and wagging vibrational modes, a SiH stretching mode modified by the presence of three oxygen atoms in the Si backbonds (O3SiH unit) and a SiOSi vibration were readily revealed. Their behavior under laser irradiation and towards the hydrogen atoms dissociated from hydrogen molecules by palladium is reported.