High reflectivity AlGaN/AlN DBR mirrors grown by MOCVD

High reflectivity (> 93.5%) distributed Bragg reflectors (DBRs) have been successfully produced using the AlGaN/AlN multilayer stacks materials system by metal-organic chemical vapor deposition (MOCVD). The peak reflectance of the DBRs was located at 320nm. The nominal Al composition is 30%, and the layer thicknesses of the different periods stack were designed for a target wavelength of 330 nm. We present reflectivity, SEM, AFM and XRD data of AlxGa1-xN/AlN Bragg reflectors grown on (0 0 0 1)oriented sapphire. The surface of the AlN/AlGaN DBRs was found to grow in quasi-two-dimensional (2D) mode, which was indicated by the atomic force microscopy (AFM). The DBR has very smooth surface and the interface was distinct. (c) 2006 Elsevier B.V. All rights reserved.