Photoluminescence from an ensemble of self-assembled quantum dots: cooperative effects

Abstract

Summary form only given. Optical properties of self-assembled quantum dots (SAQD) have attracted much interest during recent years. With a typical size of the order of the Bohr radius, SAQD's are essentially zero-dimensional objects sustaining only a few excitonic states. Given a high in-plane density, 10/sup 10/-10/sup 12/ cm/sup -2/, an array of SAQD can be viewed as a 2D system of artificial atoms with a narrow distribution of excitation energies. Recent photoluminescence (PL) experiments revealed a rather intricate structure of the PL spectrum collected from small sampling areas. Here we point out that these features of the spectrum may have a natural explanation in terms of cooperative emission from a system of SAQD. We demonstrate that the interplay between QD's coupling via the radiation field and the disorder in their excitation energies leads to a characteristic fine structure in the emission spectrum.