MOVPE growth and characterization of long-wavelength emitting quantum dots based lasers at 300 K

We observed laser operation at 300 K on the 1st excited transition of a Low-Pressure Metalorganic Vapor Phase Epitaxy grown long wavelength emitting quantum dots array inserted in an edge emitting structure, at 1.14 μm for a cavity length of 495 μm. The guiding structure presents very low absorption losses (α_i = 1.5 cm^-1). The threshold current density was estimated to be around 1200 A.cm^-2. Due to injection problems in that particular structure, we could not observe laser operation for cavity length larger than 500 μm, but we estimated that by lengthening the cavity to about 1.1 mm, laser operation should be observed at 1.25 μm, on the ground transition of the quantum dots. Laser operation is observed simultaneously on the 1st excited transition of the quantum dots and on the wetting layer, at 1.14 and 0.97 μm respectively. We attributed this phenomenon to an inefficient diffusion of the charge carriers in the wetting layer, probably related to the presence of point defects.