Cathodoluminescence study of carrier diffusion in AlGaN

This article presents a method to estimate the carrier diffusion length in the optical waveguide region of a separate confinement heterostructure (SCH) semiconductor laser. The electron incident energy dependence of waveguide and active region cathodoluminescence yields are compared with a Monte Carlo simulation of ionization processes. This procedure is applied to a SCH consisting of GaN quantum dots inserted in an Al0.27Ga0.73N/AlN optical waveguide grown by plasma assisted molecular-beam epitaxy on 6H-SiC. A diffusion length of 7.5 nm is estimated in AlGaN material at room temperature