Reduction in threshold current density of quantum well lasers grown by molecular beam epitaxy on 0.5° misoriented (111)B substrates

GaAs/AlGaAs graded-index, separate confinement heterostructure quantum-well lasers with an extremely low threshold current density ( J th ) were grown by molecular beam epitaxy on 0.5° misoriented (111)B substrates. The J th of these lasers was reduced by 20 A/cm 2 compared with that of (100)-oriented devices, which results from the quantization along the direction. The minimum J th of 158 A/cm 2 was achieved for a 490 µm long device.