Reduction of composition modulation of InGaAsP grown by atomic-hydrogen-assisted epitaxy producing improved double-heterostructure laser performance

InGaAsP laser structures with bandgap wavelengths of 1.15, 1.3 and have been grown on (100) InP substrates by gas source molecular beam epitaxy with and without a simultaneous flux of atomic hydrogen. Broad-area lasers have been fabricated and characterized. Higher threshold current densities and lower slope efficiencies are observed for active region compositions that lie deepest within the miscibility gap and which exhibit greater lateral composition modulation (LCM). The use of atomic-hydrogen-assisted epitaxy is shown to result in improved laser performance and this is attributed to a reduction in the LCM due to the surfactant action of atomic hydrogen.