PHOTOLUMINESCENCE AND TIME-RESOLVED PHOTOLUMINESCENCE CHARACTERISTICSOF INXGA((1-X))AS GAAS SELF-ORGANIZED SINGLE-LAYER AND MULTIPLE-LAYERQUANTUM-DOT LASER STRUCTURES/

The characteristics of ground and excited state luminescent transition s in In0.4Ga0.6As/GaAs and In0.35Ga0.65As/GaAs self-organized single-a nd multiple-layer quantum dots forming the active regions of lasers ha ve been studied as a function of incident excitation intensity, temper ature and number of dot layers. The results have been correlated with molecular beam epitaxial growth conditions. The threshold excitation d ensity for the saturation of the ground state increases with the numbe r of dot layers and no saturation is observed in samples with more tha n six dot layers up to an excitation power density of 2 kW/cm(2). The luminescent decay times for the ground and excited states are around 7 00 and 250 ps, respectively, almost independent of the number of dot l ayers. (C) 1997 American Institute of Physics.