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 /spl mu/m for a cavity length of 495 /spl mu/m. The guiding structure presents very low absorption losses (/spl alpha//sub i/ = 1.5 cm/sup -1/). The threshold current density was estimated to be around 1200 A.cm/sup -2/. Due to injection problems in that particular structure, we could not observe laser operation for cavity length larger than 500 /spl mu/m, but we estimated that by lengthening the cavity to about 1.1 mm, laser operation should be observed at 1.25 /spl mu/m, 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 /spl mu/m 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.