Cathodoluminescence study in AlxGa1 − xN structures

In this work, we consider a 2D model for calculation of cathodoluminescence in GaN-based structures. This model is developed using an extended generation profile and taking into account the influence of the carrier diffusion process, internal absorption and some radiative recombination processes. First, we have investigated the effect of hole diffusion length and the surface recombination velocity on the CL spectra of GaN sample grown at 800 °C by MOVPE method. Then, we have calculated the dependence of CL intensity from AlGaN alloys as a function of Al content and the electron beam energy.Results show a red shift of the CL peaks when the beam energy is varied from 2 to 10 keV at room temperature. The band-edge emission of AlxGa1 − xN shifts about 0.49 eV when the Al composition is increased from x = 0.18 to 0.38. Comparison of the experimental spectra with simulations shows a good agreement.