Time-resolved photoluminescence of InGaAs nanostructures different in quantum dimensionality

The time-resolved photoluminescence of quantum-confined InGaAs heterostructures grown on GaAs substrates is studied by time-correlated single photon counting. The heterostructures have different dimensionalities: the structures are formed as quantum dots, quantum wells, and structures of transition dimensionality (quantum well-dots). It is found that the room-temperature photoluminescence decay time of the samples substantially depends on their dimensionality and corresponds to 6, 7, and $>$ 20 ns for quantum dots, well-dots, and wells, respectively. It is thought that the presence of localization centers for charge carriers can be responsible for the experimentally observed shortening of the photoluminescence time in the heterostructures.