TIME-RESOLVED LUMINESCENCE IN INP ALINAS TYPE-II QUANTUM-WELL STRUCTURES/

We report an experimental study, by means of ps time-resolved luminesc ence correlations, of the free carrier relaxation in type II InP/AlInA s heterostructures. The decay times are measured in the energy range c orresponding to the spatially indirect electron-hole recombination and at low excitation power in order to avoid band-filling effects. These times are in the range of a few tens of ps. They are much shorter tha n the decay time of the spectrally integrated and correspond to the pl asma thermalization times. From the experimental data, the presence of a large amount of traps or carriers due to a residual doping is infer red and it is shown that they play a fundamental role in the recombina tion. Finally, from the analysis of the time-resolved correlations at different excitation intensities, we confirmed the contribution to the luminescence of transitions involving different valence subbands.