Self-assembled In/sub 0.5/Ga/sub 0.5/As quantum-dot lasers with doped active region

Self-assembled In/sub 0.5/Ga/sub 0.5/As quantum-dot lasers with different doping schemes in the active region are investigated. Their lasing wavelength, characteristic temperature, quantum efficiency, and internal loss are characterized and correlated with the size, uniformity, and density of the quantum dots as revealed by atomic force microscopy. Continuous-wave operation of Be-doped quantum-dot lasers has been achieved. Undoped In/sub 0.5/Ga/sub 0.5/As quantum-dot lasers with a characteristic temperature as high as 125 K above room temperature have also been demonstrated.