Thermalization and band renormalization in the zero-dimensional electron-hole system in InGaAs/GaAs quantum dots

We have investigated thermalization and band renormalization in zero-dimensional electron-hole plasmas in InGaAs/GaAs quantum dots with geometrical widths down to 24 nm by time-resolved photoluminescence spectroscopy. Our experiments indicate a reduced relaxation of carriers in quantum dots with decreasing size, while the carriers in the dots seem to be thermally distributed on the discrete energy levels. Exchange-correlation interaction of the carriers in the dots lead to a renormalization of the bandgap.