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_0.5Ga_0.5As/GaAs QD LD grown with ALMBE are reported. In_0.5Ga_0.5As/GaAs QD LD was grown on [001]n-GaAs substrate. The total density of 3-stacked QD layers is ∼5×10¹⁰/cm², 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 μm. Light-current curve of the broad area laser diode with 2 mm cavity length and 200 μm width at temperature of 15 °C was also shown. The current injection conditions were 1 μs per 1 ms and the lasing threshold current is 2 A, which corresponds to a threshold current density of 500 A/cm². The external quantum efficiency is 40% while the internal quantum efficiency is 66% with a 45 cm^-1 internal loss.