We address the problem of the photoluminescence of a quantum (QD) dot in a nanocavity, with focus on the case of nonzero detuning. In this regime, experiments have shown that strong emission from the cavity-like peak is still present for dot-cavity detuning exceeding 10 meV, which seems puzzling. We will discuss the general theory of cavity feeding, due to the relaxation and recombination kinetics of a multiply excited QD. We first compute the multi-exciton manifolds using a configuration-interaction scheme, starting from a truncated single-particle basis. We then run Monte-Carlo paths of excitation-emission kinetics on these states. This allows to extract photoluminescence spectra and two-photon correlation curves. The agreement with experimental data[1, 2] is very good. Our result shows unambiguously that the cavity feeding mechanism at large detunings can be attributed to excited-state multiexciton radiative decay (mostly biexcitons), also involving states in the wetting layer continuum.
Nicolas Grandjean, Raphaël Butté, Johann Nicolaï Stachurski, Gordon Jens Callsen, Sebastian Pascal Tamariz Kaufmann, Kanako Shojiki
Jacques-Edouard Moser, Etienne Christophe Socie, Andrés Burgos Caminal, Brener Rodrigo De Carvalho Vale