HydrolysisandSilanizationoftheHydrosiliconSurfaceof.docVIP

Hydrolysis and Silanization of the Hydrosilicon Surface of Freshly Prepared Porous Silicon by an Amine Catalytic Reaction Dongsheng Xu 1), Lin Sun, Hongliang Li, Lei Zhang, Guolin Guo, Xinsheng Zhao and Linlin Gui State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China Abstract A novel catalytic reaction using a trace of organic amine as the catalyst enables hydrolysis of the silicon-hydrogen groups on the fresh prepared porous silicon (PS), generating the hydroxyl-terminated surfaces without oxidization of the back Si-Si bonds. The reactivity of the hydroxyl-terminated surfaces with various silanization reagents was investigated, which proceeds by abstraction of the surface-OH to form an organic monolayer of Si-O-Si-C bonds and importantly retains the intrinsic structural properties of the PS layers. Furthermore, an in situ silanization modification of the silicon-hydrogen surfaces has been established. Stability testing shows that the resulting organic monolayers are densely packed and are shown to be highly stable under a variety of conditions including hot water, hot organic solvent, acid, and base, but can be removed by a HF rinse. Introduction The desirability of constructing silicon-based optoelectronic device and chemical and biological sensors has prompted the considerable development in the surface chemistry of luminescent porous silicon (PS) [1-7]. The hydrogen-terminated PS surfaces, which is obtained by electrochemical etching in fluoride containing media, oxidizes slowly in air, leading to slow degradation of photoluminescence (PL) and concomitant degradation of the electronic properties [6]. Many studies have been focused on formation of silicon oxide species under thermal, electrochemical, or chemical oxidation conditions to stabilize the H-terminated surface [6, 7]. Although this approach lowers the reacti