OPTICAL INVESTIGATION OF INTERFACE ROUGHNESS AND DEFECT INCORPORATION IN GAAS/ALGAAS QUANTUM-WELLS GROWN WITH AND WITHOUT GROWTH INTERRUPTION

We report a comparative analysis of photoluminescence and photoluminescence excitation of GaAs/AlGaAs quantum well structures grown by molecular beam epitaxy with and without growth interruption, which clearly indicates the improvement of interface quality when interruptions are used during growth. Time resolved spectroscopy, together with the temperature dependence of the integrated radiative recombination intensity, are used as a sensitive probe of the defect incorporation, which is usually observed to increase as a consequence of growth interruptions. We find that a significant increase of both extrinsic photoluminescence and nonradiative processes is not a necessary consequence of growth interruptions, unlike recent reports in the literature. We conclude that growth interruptions are compatible with the growth of high quality quantum well structures with a very high radiative efficiency.