The characteristics of 3-stacked InGaAs/GaAs quantum dot lasers grown by atomic layer molecular beam epitaxy

In this presentation, the electrical and optical properties of In/sub 0.5/Ga/sub 0.5/As/GaAs QD LD grown with ALMBE are reported. In/sub 0.5/Ga/sub 0.5/As/GaAs QD LD was grown on [001]n-GaAs substrate. The total density of 3-stacked QD layers is /spl sim/5/spl times/10/sup 10//cm/sup 2/, and the average height and width of each QD are 7 and 45 nm, respectively. A room temperature photoluminescence (PL) peak is shown to have linewidth of 31.3 meV and the peak wavelength is about 1.24 /spl mu/m. Light-current curve of the broad area laser diode with 2 mm cavity length and 200 /spl mu/m width at temperature of 15 /spl deg/C was also shown. The current injection conditions were 1 /spl mu/s per 1 ms and the lasing threshold current is 2 A, which corresponds to a threshold current density of 500 A/cm/sup 2/. The external quantum efficiency is 40% while the internal quantum efficiency is 66% with a 45 cm/sup -1/ internal loss.