Population Dynamics of Excitons in Silicon Nanocrystals Structures under Strong Optical Excitation
We report on the experimental and theoretical studies of population/depopulation dynamics of excitons in the structures with Si nanocrystals in SiO2 matrix (nc-Si/SiO2) under strong optical excitation. The experimental results are explained using a phenomenological model based on rate equations for coupled system of energy donors (excitons) and energy acceptors (erbium ions). Exciton luminescence is found to exhibit superlinear dependence for Er-doped samples. At the same time the Er-related luminescence at 1.5 μm shows a saturation of the intensity and shortening of the lifetime, which are attributed to the population inversion of the Er ions states. The obtained results demonstrate that nc-Si/SiO2:Er systems can be used for applications in Si-based optical amplifiers and lasers, compatible with planar Si-technology.
S. J. CHUA, J. H. TENG, O. WADA, R. DE LA RUE and X. H. TANG
O. A. Shalygina et al., "Population Dynamics of Excitons in Silicon Nanocrystals Structures under Strong Optical Excitation", Advanced Materials Research, Vol. 31, pp. 196-198, 2008