The exciton binding energy, the energies of the basic radiative exciton transition, and the zero-phonon radiative lifetime of excitons in Si quantum dots embedded in the SiOx matrix were 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 Si quantum dots were calculated, and the kinetics of the photoluminescence relaxation was considered. The theory was compared with the experiment. It was shown that, for nanostructures involving Si quantum dots with diameters smaller than 4nm, the governing factor in the broadening of the spectral photoluminescence bands was the effect of mesoscopic quantum fluctuations. In this case, either an even one dangling bond at the interface, or one intrinsic point defect, or one foreign atom located inside the small-sized nanocrystallite or in its close surroundings produces a pronounced effect on the energy of the exciton transition.

Exciton Characteristics and Exciton Luminescence of Silicon Quantum Dot Structures. I.M.Kupchak, D.V.Korbutyak, Y.V.Kryuchenko, A.V.Sachenko, I.O.Sokolovskiĭ, O.M.Sreseli: Semiconductors, 2006, 40[1], 94-103