Scalable etched-pillar, AlAs-oxide defined vertical cavity lasers

Etched-pillar, bottom-emitting vertical cavity lasers have been fabricated using lateral oxidation of AlAs. The devices have threshold currents as low as 315 μA for a 4 μm×4 μm, three quantum well active region. Using the data and a numerical model the authors extract excess optical and carrier losses and an effective surface recombination velocity for the devices. The data show that size dependent optical scattering persists as the lasers are scaled to smaller sizes, but lateral carrier leakage is suppressed, allowing for scaling of lasers to small sizes to achieve lower threshold currents