Kinetics of thermalized luminescence of a single quantum dot at room temperature

Abstract

We have developed a theory of transient secondary emission of a single quantum dot from the lowest energy states of electron-hole pairs. We consider a process in which laser pulses excite a certain highenergy state of electron-hole pairs of a quantum dot at room temperature, with the electronic subsystem then relaxing to low-energy states and photons being emitted. Therefore, the investigated secondary emission process is thermalized luminescence. For definiteness, the developed model takes into account two states of electron-hole pairs that contribute to the luminescence. We have analyzed the dependence of the secondary emission signal on the energy gap between these states, the value of which is determined by the quantum dot size. In terms of the Pauli master kinetic equation, an analytical expression for the time dependent signal of the thermalized luminescence has been obtained. We show that, as the spectral width of the exciting laser pulse tends to zero, this expression yields the signal of stationary luminescence.