High-performance 980-nm quantum-well lasers using a hybrid material systemof an Al-free InGaAs-InGaAsP active region and AlGaAs cladding layers grown by metal-organic chemical vapor deposition

We report on the material growth and fabrication of high-performance 980-nm strained quantum-well lasers employing a hybrid material system consisting of an Al-free InGaAs-InGaAsP active region and AlGaAs cladding layers. The use of AlGaAs cladding instead of InGaP provides potential advantages in f lexibility of laser design, simple epitaxial growth, and improvement of sur face morphology and laser performance. The as-grown InGaAs-InGaAsP(1.6 eV)- AlGaAs(1.95 eV) lasers achieve a low threshold current density of 150 A/cm( 2) (at a cavity length of 1500 mu m), internal quantum efficiency of simila r to 95%, and low internal loss of 1.8 cm(-1). Both broad-area and ridge-wa veguide laser devices are fabricated. For 100-mu m-wide stripe lasers with a cavity length of 800 Irm, a slope efficiency of 1.05 W/A and a characteri stic temperature coefficient (T-0) of 230 K are achieved. The lifetime test demonstrates a reliable performance. The comparison with our fabricated In GaAs-InGaAsP(1.6 eV)-AlGaAs(1.87 eV) lasers and Al-free InGaAs-InGaAsP (1.6 eV)-InGaP lasers are also given and discussed. The selective etching betwe en AlGaAs and InGaAsP is successfully used for the formation of a ridge-wav eguide structure. For 4-mu m-wide ridge-waveguide laser devices, a maximum output power of 350 mW is achieved. The fundamental mode output power can b e up to 190 mW with a slope efficiency as high as 0.94 W/A.