Room-temperature continuous operation of GaAs/AlGaAs lasers grown on Si by organometallic vapor-phase epitaxy

Abstract

Graded‐index separate‐confinement heterostructure single‐quantum‐well GaAs/AlGaAs diode lasers exhibiting continuous (cw) operation at room temperature have been grown on a Si substrate by organometallic vapor‐phase epitaxy, without the use of molecular‐beam epitaxy. To improve the quality of the laser structure, a defect‐filtering layer was incorporated between this structure and a GaAs buffer layer about 1.5 μm thick grown on the substrate. Of four types of defect‐filtering layers investigated, the most effective was one grown with thermal cycling, which made it possible to obtain pulsed threshold current densities as low as 350 A/cm² for broad‐stripe lasers with a cavity length of 500 μm. Ridge‐waveguide lasers with this type of defect‐filtering layer have exhibited cw threshold currents as low as 25 mA and a differential quantum efficiency of 55%.