Many carrier effects in self-assembled InP quantum dots

Excitation power density dependence of InP self-assembled quantum dots (SADs) was investigated under band-to-band excitation in a Ga0.5In0.5P matrix by means of macro- (conventional) and micro-spectroscopy. State filling of confined excitonic states was studied in detail by micro-photoluminescence (μ-PL) spectra and images. The efficiency of the state filling differs from dot to dot, which depends on the inflow and outflow rates of the excitons. Sharp μ-PL lines from a single confined exciton and biexciton were clearly observed. The observed biexciton binding energy of an InP SAD is a few times larger than that of the bulk InP, suggesting that the multi-exciton states are stabilized because of the confinement.