An Initial Study of Ultraviolet C Optical Losses for Monolithically Integrated AlGaN Heterojunction Optoelectronic Devices

摘要

An initial study of losses in n-Al_xGa_(1-x)N planar waveguides at λ_(emission) ≈ 280 nm using monolithically integrated Al_xGa_(1-x)N multiple quantum wells (MQWs)- based light-emitting diodes and detectors is presented. The epilayer structure for the integrated devices is grown on an AlN (3.5 μm thick) template over sapphire substrates. Emitter–detector optical coupling and the directional independence of radiation within the epistructure are experimentally established. A model for estimating the attenuation coefficient under these conditions is developed. The attenuation coefficient for a planar n-Al_(0.65)Ga_(0.35)N waveguide is measured to be 5–6 cm~(-1), and it primarily arises from the free-carrier absorption rather than surface roughness-dependent Rayleigh scattering.