Thermal Route for Chemical Modification and Photoluminescence Stabilization of Porous Silicon

Abstract

This paper describes photoluminescence (PL) stabilization through chemical modification of freshly prepared porous silicon (PSi) surfaces. As-anodized PSi surfaces react with 1-alkenes, non-conjugated dienes and aldehydes at elevated temperatures to form organic monolayers covalently bonded to the surface. This thermal route is very general and tolerant of different functional groups. We have characterized these organic monolayers using diffuse reflectance infrared Fourier-transform (DRIFT), Auger and Raman spectroscopies. The PL intensity and peak energy of the as-anodized PSi is not affected by the chemical functionalization. Aging these derivatized PSi samples in ambient air has no effect on the PL. In fact, it is completely preserved even when they are steam treated for six weeks at 70 °C and 100% humidity. This treatment completely destroys the structural integrity of H-terminated PSi.