LUMINESCENCE OF BIEXCITONS IN CUBR QUANTUM DOTS

In this contribution, luminescence experiments at CuBr quantum dots gr own in a wide range of sizes in the weak confinement regime (R greater -than-or-equal-to a(B)) will be presented. In intensity-dependent lumi nescence measurements with ns-pulses, for each dot size two peaks can be resolved and are attributed to exciton and biexciton transitions, r espectively. From time-resolved luminescence after ps-excitation, we o btain additional insight into the dynamics of biexciton formation and decay. We observe a delayed onset and a faster decay of the biexciton luminescence compared to the exciton luminescence. The experimental va lues for the energetic difference of the exciton and the biexciton pea k agree very well with recent numerical calculations for the biexciton binding energy, predicting an increase for decreasing dot sizes. An e xception are very small dots where e.g. due to interface-related state s these calculations can no longer be applied.