Electron-hole dynamics in MOCVD-grown InGaAs/GaAs quantum dots emitting at 1.3 mu m

A study of the electron-hole relaxation dynamics in metalorganic chemical vapour deposition (MOCVD)-grown InGaAs/GaAs quantum dots (QDs) emitting at 1.3 mum is presented. The photoluminescence (PL) rise and decay times are measured as functions of carrier density and temperature, showing that the electron-hole relaxation into the QD ground state occurs within a few picoseconds. We find that the emission of two longitudinal optical (LO) phonons is the dominant capture process at room temperature, whereas carrier-carrier scattering dominates the relaxation process at low temperatures and high carrier densities. Finally, the MOCVD-grown QD structures show relatively small PL quenching; the quenching is caused by thermal carrier escape from the QD ground state via absorption of two LO phonons.