Abstract
An initial study of losses in n-AlxGa1-xN planar waveguides at lambda(emission) approximate to 280 nm using monolithically integrated AlxGa1-xN 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 mu m 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-Al0.65Ga0.35N 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.