STERIC CONSIDERATIONS IN THE AMINE-INDUCED QUENCHING OF LUMINESCENT POROUS SILICON

in this work we report a study of the effects of the exposure of selec ted alkylamines on the visible photoluminescence (PL) of porous Si (PS ), including their intrinsic quenching ability, time scales of restora tion, and the additional influence of a weak acid (TFA) on the restora tion of FL. While comparable percentages of porous Si PL can be quench ed with a given amount of n-propyl-, n-butyl-, or n-pentylamine, monit oring the extent of PL restoration over time reveals discriminating be havior between n-pentylamine and n-propyl/n-butylamine(s). As expected , increasing the porosity of the matrix does facilitate the restoratio n of FL. The introduction of trifluoroacetic acid (TFA) also speeds up the restoration of amine-quenched porous Si FL. Effects of organoamin e exposure are also examined in light of any modification of the surfa ce composition of porous Si, as probed by infrared spectroscopy (IR). The results reported here suggest that the diffusion of small amines w ithin the porous Si matrix (as reflected in PL quenching/restoration b ehavior) is a function of the steric bulk of the amine chosen and the porous matrix where luminescent silicon nanoclusters reside.