Nonradiative resonance energy transfer between semiconductor quantum dots
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DISORDER, AND PHASE TRANSITION IN CONDENSED SYSTEM
Nonradiative Resonance Energy Transfer between Semiconductor Quantum Dots D. M. Samosvat*, O. P. ChikalovaLuzina, and G. G. Zegrya** Ioffe Physicotechnical Institute, Russian Academy of Sciences, St. Petersburg, 194021 Russia * email: [email protected] ** email: [email protected] Received May 27, 2014
Abstract—A microscopic analysis of the mechanisms of nonradiative energy transfer in a system of two semi conductor QDs caused by Coulomb interaction of donor and acceptor electrons is performed. The energy transfer rate is calculated for QDs based on III–V compounds using the Kane model. Conditions are ana lyzed under which energy transfer from a donor to an acceptor is possible. The mixing in of the p states of the valence band to the s states of the conduction band is found to give rise to additional contributions to the matrix element of energy transfer. It is shown that these additional contributions play a considerable role in the energy transfer process at distances between QDs close to contact distances or much greater. The influ ence of the exchange interaction on the energy transfer mechanism is analyzed, and it is shown that this inter action should be taken into account for a quantitative description of the energy transfer when QDs are sepa rated by a distance close to the contact distance. DOI: 10.1134/S1063776115060138
ies revealed the role of nonradiative energy transfer in biological systems (in particular, in photosynthesis) [12] (see also references in [13]). The method based on energy transfer between organic dye molecules is now widely used in biological and medical experiments (see, e.g., [14, 15]).
1. INTRODUCTION The electronic excitation energy transfer between quantum systems one of the important fundamental problems of modern physics [1]. The electronic energy is transferred from an energy donor (atom, molecule, semiconductor QD or quantum well) to an energy acceptor. There are different energy transfer mecha nisms: the wellknown radiative mechanism, in which a donor emits a photon absorbed by an acceptor (see, e.g., [2]); the nonradiative mechanism, when the elec tronic energy is transferred from a donor to an accep tor in a onestep process, unlike radiative energy transfer [3, 4]; and the electron transfer mechanism, in which the excited electron of the energy donor is transferred to the acceptor [5]. The two latter mecha nisms cause donor luminescence quenching. How ever, the first leads to sensitized fluorescence of accep tors, while the second leads to the formation of posi tively charged donors and negatively charged acceptors (in the case of molecules, to pairs of ions). These mechanisms are fundamentally different: non radiative energy transfer occurs due to Coulomb inter action between donor and acceptor electrons, the electron transfer being determined only by the overlap of the wavefunctions of the corresponding donor and acceptor states. The nonradiative energy transfer was first observed in 1923 in exp
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