Lattice-matched Al0.95Ga0.05AsSb oxide for current confinement in InP-based long wavelength VCSELs

We examine, for the first time, Al0.95Ga0.05AsSb-oxide as the lateral current confining layer for InP-based optoelectronic devices including vertical cavity surface emitting lasers. In this paper, Al0.95Ga0.05AsSb-oxide confined broad area edge emitting lasers were used to study current confinement and optical loss. Results show that the threshold current density scales effectively down to a confining layer width of 6.5 *mm and the differential efficiency remains unchanged down to 4 *mm, indicating no aperture induced excess loss. This suggests that thin AlGaAsSb layers, at low oxidation temperatures, may get oxidized homogeneously without leaving metallic-Sb behind.