Photoluminescence stabilization of anodically-oxidized porous silicon layers by chemical functionalization

Electrochemical oxidation of porous silicon (PSi) produces a surface that is covered with native silicon-hydrogen (Si-H-x) bonds and regions with oxidized Si-Si back-bonds (OSi-H-x). Such anodically oxidized PSi layers were chemically modified using 1-decene under thermal conditions. The hydrosilylation reaction consumes mainly the nonoxidized Si-H-x bonds and yields a surface with oxidized and alkylated regions that were characterized using transmission IR and Raman spectroscopies. The brightest photoluminescence (PL) was obtained when the PSi sample was anodized in 1 M sulfuric acid (H2SO4) at 3 mA/cm(2) for 5 min. The chemical process preserves the PL and the physical properties of the porous layer. The derivatized PSi surfaces are stable in boiling CCl4 and in water. (C) 2002 American Institute of Physics.