Influence of electronic coupling on the radiative lifetime in the (In,Ga)As/GaAs quantum dot–quantum well system

In this paper, we present time-resolved photoluminescence of self-assembled (In,Ga)As quantum dots (QDs) coupled to an In${}_{x}$Ga${}_{1\ensuremath{-}x}$As quantum well (QW) through a thin GaAs barrier. The coupling strength is controlled by the well width and material composition and has a direct influence on the QD--QW system ground-state radiative lifetime, which increases from 1.1 up to 1.82 ns as the coupling strength increases. A thorough explanation is given for the reduction of the fundamental transition oscillator strength in the interacting system induced by the transformation of related eigenstates from a noncoupled to a coupled regime. The experimental observations have been fully confirmed by the results of three-dimensional band structure calculations of a coupled QD--QW system within the framework of eight-band k$\ifmmode\cdot\else\textperiodcentered\fi{}$p theory.