On the temperature dependence of silicon quantum dot photoluminescence

A model of radiative and nonradiative transitions in silicon quantum dots is presented, which describes the photoluminescence temperature dependence of the ion-synthesized ensembles of Si nanocrystals in SiO2. A four-level system of transitions is considered that takes into account thermally activated processses and exchange splitting of the ground energy state of exciton in a silicon nanocrystal into triplet and singlet levels, the transfers from which to the ground state are responsible for the luminescence. The temperature dependence of monochromatic photoluminescence components was obtained based on the stationary solution of the system of kinetic equations for the population of levels that satisfactory describes the experimental data. The exciton energy splitting values depending on the energy of emitted photons were found and compared with the data in the literature.