Quantum dot lasers based on a stacked and strain-compensated active region grown by metal-organic chemical vapor deposition

We demonstrate an InAs/GaAs quantum dot sQDd laser based on a strain-compensated, three-stack active region. Each layer of the stacked QD active region contains a thin GaP sDao=−3.8% d tensile layer embedded in a GaAs matrix to partially compensate the compressive strain of the InAs sDao=7% d QD layer. The optimized GaP thickness is ,4 MLs and results in a 36% reduction of compressive strain in our device structure. Atomic force microscope images, room-temperature photoluminescence, and x-ray diffraction confirm that strain compensation improves both structural and optical device properties. Room-temperature ground state lasing at l=1.249 mm, Jth =550 A/cm2 has been demonstrated. © 2005 American Institute of Physics. fDOI: 10.1063/1.1926413g