Exciton characteristics and exciton photoluminescence of silicon QD structures

The exciton binding energy, the energies of the basic radiative exciton transition, and the zero- phonon radiative lifetime of excitons in silicon quantum dots embedded in the SiOx matrix are calculated in effective mass approximation with quadratic dispersion relation. In addition, the spectra of steady-state photoluminescence and of time-resolved photoluminescence of excitons in the silicon quantum dots are calculated, and the kinetics of the photoluminescence relaxation is considered. The theory is compared with the experiment. It is shown that, for nanostructures involving silicon quantum dots with diameters smaller than 4 nm, the governing factor in the broadening of the spectral photoluminescence bands is the effect of mesoscopic quantum fluctuations