Intrinsic non-exponential decay of time-resolved photoluminescence from semiconductor quantum dots

Abstract

A general introduction is presented to the recently observed intrinsic non-exponential and excitation intensity-dependent decay of time-resolved photoluminescence from semiconductor quantum dots. The commonly used two-level approximation fails in this situation since it relies on fully correlated carriers. In a semiconductor, however, the correlations are subject to scattering and dephasing processes. Hence, carriers are in general not fully correlated. It is shown that this effect leads to a non-exponential and excitation intensity-dependent decay of photoluminescence. The origin of the phenomenon is discussed in detail for a simplified situation. The full problem is studied numerically on the basis of a microscopic theory that includes Coulomb and carrier-photon correlation effects. © 2009 Springer-Verlag Berlin Heidelberg.