OPTIMIZATION AND CHARACTERISTICS OF AL-FREE STRAINED-LAYER INGAAS/GAINASP/GAINP SCH-QW LASERS (LAMBDA-SIMILAR-TO-980-NM) GROWN BY GAS-SOURCE MBE

Aluminum-free strained-layer InGaAs/GaInAsP/GaInP separate confinement heterostructure quantum well lasers emitting at 980 nm have been demonstrated. In particular, we have studied optimization of the laser structure and the growth conditions using gas-source molecular beam epitaxy. Closely optimized parameters have been found. The lasers resulting from this work exhibited very good device properties. The lowest threshold current densities obtained for the single-quantum-well laser and three-quantum-well laser were 72 and 150 A/cm2, respectively. The internal quantum efficiency was 94%, and the internal waveguide loss was 5.4 cm-1. The transparency current density and gain coefficient were 33 A/cm2 and 0.091 cm . mum . A-1, respectively. A high characteristic temperature ranging from 220 to 280 K was obtained. The ridge waveguide laser exhibited a far-field pattern with a vertical divergence of 47-degrees and a lateral divergence of 13-degrees. These characteristics compare favorably with the best values reported for InGaAs/AlGaAs quantum-well lasers.