Free-carrier absorption in Si nanocrystals probed by microcavity photoluminescence

Resonant photoluminescence of Si-nanocrystals is used to determine their free-carrier absorption cross-section (sigma
_FCA
) at visible/near-infrared wavelengths. Rate-equation modeling, including ensemble effects, yields sigma
_FCA
= 7:8 times 10
^-18
cm
²
at 895 nm. This has implications for Si-based laser design at various wavelengths.