III-nitride vertical resonant cavity light-emitting diodes with hybrid air-gap/AlGaN-dielectric distributed Bragg reflectors

Abstract

We report III-N surface-emitting resonant-cavity light-emitting diodes (RCLEDs) at λ = 375 nm using a novel hybridmirror approach. The hybrid mirrors consist of 5 pairs of air-gap/AlGaN distributed Bragg reflector (DBR) at the bottom side of the vertical cavity and HfO₂/SiO₂ dielectric DBR (DDBR) on the top to facilitate the formation of a resonant cavity for nitride-based surface light emitting diodes. The air-gap/AlGaN DBR replaces the conventional thick stack of semiconductor DBR to achieve high reflectivity. Hybrid-mirror III-N RCLEDs with airgap/AlGaN DBR mirror were fabricated and the results showed that the III-N RCLEDs achieved high current density operation up to 40 kA/cm² with a peak emission wavelength atλ = 375 nm and a full-width-half-maximum (FWHM) of 9.3 nm at room temperature.