The real part of the frequency-dependent dielectric function ε1(ω) and the light-absorption coefficient α(ω), of Si slabs confined within SiO2 barriers have been calculated as a function of Si-slab thickness dsi. The calculation uses the imaginary part ε2(ω) of the dielectric function obtained from tight-binding calculations. The resulting static dielectric constants are found to increase with the decreasing Si-slab width, contrary to some reported theoretical results for H-terminated Si or pure-Si clusters. The calculated integrated light absorption in the range 1.0-2.6 eV is a maximum for for slabs with dsi∼20 Å, in agreement with experimental work on light emission from Si/SiO2 superlattices and other oxidized Si nanostructures.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)