Organometallic vapor phase epitaxy of high-performance strained-layer InGaAs-AlGaAs diode lasers

Graded-index separate-confinement heterostructure single-quantum-well lasers incorporating a strained In_xGa_1-xAs active layer, with x⩽0.25, and AlGaAs confining layers have been grown on GaAs substrates by low-pressure organometallic vapor phase epitaxy. The emission wavelength increases from 0.85 μm for x=0 to 1.03 μm for x=0.25. The growth of GaAs layers bounding the InGaAs active layer significantly improves laser performance. For devices with x =0.25 and a cavity length L of 500 μm, the pulsed threshold current density J_th is reduced from 550 A/cm² for structures without bounding layers to 125 A/cm² for structures with 10-nm-thick bounding layers, while the differential quantum efficiency η_d is increased from 46 to 80%