REACTION OF METHANOL WITH POROUS SILICON

The reaction of both porous silicon and hydrogen covered (passivated) porous silicon with methanol was investigated. Adsorption of methanol onto porous silicon at 300 K resulted in cleavage of the O-H bond and formation of Si-OCH3 and Si-H surface species. Heating of these surfac e species to similar to 500 K caused breakage of both the C-O and C-H bonds. This resulted in the formation of Si-H surface species and the incorporation of oxygen and carbon into the porous silicon layer. Atte mpts to adsorb methanol onto passivated porous silicon proved unsucces sful until removal of the Si-H surface species commenced at 600 K. In addition to oxygen and carbon incorporation, Si-OCH3, Si-CH3, and Si-H surface species were observed when excess CH3OH(g) was used to drive the decomposition reaction. The stability of the Si-CH3 species when e xcess CH3OH(g) was present is likely due to oxygen and/or carbon passi vation of the silicon surface.