Physico−Technical Research Institute of Lobachevsky State University of Nizhni Novgorod:

S. N. Nagornykh

V. I. Pavlenkov

A. N. Mikhaylov
A. I. Belov

V. A. Burdov

D. I. Tetelbaum

Institute for Physics of Microstructures RAS:

L. V. Krasilnikova
D. I. Kryzhkov

A model of radiative and nonradiative transitions in silicon quantum dots is presented that describes the temperature dependence of photoluminescence of ion−synthesized ensembles of Si nanocrystals in SiO₂. The four−level scheme of transitions is considered taking into account thermally activated processes and exchange splitting of the ground state of excited exciton to triplet and singlet sublevels, transitions from which are responsible for the luminescence. The expression for temperature dependence of the monochromatic photoluminescence components that is in agreement with a number of analogous dependencies from literature is derived on the basis of solution of a system of kinetic equations. The obtained expression describes adequately experimental results of the given work and allows to determine the splitting value for the exciton state in dependence on the energy of emitted photons, i.e. the nanocrystal size.

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