B. Swerydakrawiec et al., A COMPARISON OF POROUS SILICON AND SILICON NANOCRYSTALLITE PHOTOLUMINESCENCE QUENCHING WITH AMINES, Journal of physical chemistry, 100(32), 1996, pp. 13776-13780
We report here a comparison of the ability of the monodentate Lewis ba
se n-propylamine and the bidentate molecule ethylenediamine to quench
the photoluminescence of light-emitting silicon in three different str
uctural environments. These include porous silicon fabricated from p-t
ype substrates; porous silicon from n-type substrates, and Si nanocrys
tallites derived from porous silicon. Both types of porous Si substrat
es were characterized by conventional transmission electron microscopy
, while the Si nanocrystallites were characterized by high-resolution
transmission electron microscopy. The fractional changes in photolumin
escence as a consequence of amine addition were measured and fitted to
a static equilibrium model from which adduct formation constants were
calculated. It is found that the Si lumophores embedded in the porous
oxides on n- and p-type substrates interact similarly with n-propylam
ine and ethylenediamine; however, ultrasonic extraction of the nanacry
stalline Si fragments from the porous oxide layers and subsequent expo
sure to these amines reveals a near order of magnitude difference betw
een the equilibrium constants for n?-propylamine (log K similar to 4.9
) and ethylenediamine (log K similar to 5.8) addition.