We
report strong enhancements of the effective absorption cross section
and photoluminescence (PL) intensity of silicon quantum dots (Si QDs)
with 2.8–6.8 nm in diameter in a highly scattering dielectric
medium. The scattering medium is a polymer thin film with submicrometer
size pores inside, supporting the resonant cavity modes in the visible
range. By the scattering associated with the cavity modes, efficient
light trapping into a polymer film with ∼1 μm in thickness
is achieved, which leads to 30–40 times enhancement of the
effective absorption cross section of embedded Si QDs in a green–red
wavelength range. The scattering medium can also enhance up to 40
times the PL of QDs. Detailed analysis reveals that the enhancements
of the extraction efficiency as well as the excitation efficiency
contribute to the PL enhancement
