Tunnel contact junction native-oxide aperture and mirror vertical-cavity surface-emitting lasers and resonant-cavity light-emitting diodes

Abstract

Vertical-cavity surface-emitting lasers (VCSELs) and resonant-cavity light-emitting diodes (RCLEDs) are demonstrated with high index contrast distributed Bragg reflectors (DBRs) on either side of a λ-thickness cavity (λ∼980 nm). The devices, with tunnel contact junctions making possible lateral electron current excitation, have a lower 6.5 period native-oxide-based AlxOy/GaAs DBR and an upper reflector that is either a 2–4 period AlxOy/GaAs DBR, a 1–2 period SiO2/ZnSe DBR, a λ/4-thickness layer of AlxOy (antireflecting), or no mirror at all. The AlxOy/GaAs DBRs and a buried-oxide-defined current aperture are formed by selective oxidation of the high Al composition AlxGa1−xAs layers. Device characteristics are observed as a function of the upper DBR periodicity (reflectivity). Devices with upper reflectivities of R≳99% operate as VCSELs while those with less reflectivity R≲96% operate as RCLEDs, some with external differential quantum efficiencies as high as η∼27% and narrow spectral emission (Δλ∼50 Å).