Carrier dynamics in InAs/GaAs submonolayer stacks coupled to Stranski-Krastanov quantum dots

Abstract

Time-resolved photoluminescence experiments on a coupled system of Stranski-Krastanov quantum dots (SK QDs) overgrown by a stack of submonolayer (SML) depositions reveal an acceleration of the carrier dynamics in the SML stack mediated by distance-dependent transfer processes. The coupling between an SML stack and an SK QD layer increases with decreasing spacer thickness $d$, which separates the two different nanostructure systems. This control parameter $d$ as well as the optical transition energies of the SML stack can be adjusted via the growth process. The observed photoluminescence dynamics of the combined SK QD and SML system is well described by a rate equation model which includes both pure zero-dimensional and zero-dimensional\char21{}two-dimensional states.