Carrier relaxation dynamics in quantum dots: Scattering mechanisms and state-filling effects

Stressor-induced ${\mathrm{In}}_{\mathrm{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$As quantum dot structures of high structural quality allow a detailed experimental investigation of carrier relaxation between distinct zero-dimensional quantized states. Time-resolved photoluminescence studies combined with appropriate model calculations show that state filling effects, Coulomb scattering, and acoustic phonon scattering determine the relaxation scenario in a way characteristic for a zero-dimensional electronic system. These investigations allow a quantitative estimation of the inter-dot-level relaxation rates mediated by (i) Coulomb scattering and (ii) acoustic phonon scattering.