AMORPHOUS GAAS PASSIVATION OF ION-BEAM-ETCHED INGAAS VERTICAL-CAVITY SURFACE-EMITTING LASERS

We report the successful application of a low-temperature-grown amorph ous GaAs (a-GaAs) layer for surface passivation of InGaAs vertical-cav ity surface-emitting lasers. The deposition of an a-GaAs layer on ion- beam-etched laser posts showed a significant improvement, more than 20 %, in the threshold current density and the differential quantum effic iency. We also observed an increase in the maximum currents maintainin g a stable fundamental transverse mode for 15-mu m- and 20-mu m-diamet er devices which was the antiguide effect of the a-GaAs layer with hig h refractive index.