We report on lattice-matched AllnN/GaN distributed Bragg reflectors (DBRs) with improved overgrowth of the AllnN layers. Typically, AllnN layers are exposed to high temperatures when changing to GaN growth conditions. Uncapped AllnN surfaces stiffer from In desorption leading to formation of 2 am thick AIN interface layers with micro-cracks at the AllaN surface. Capping the AllnN with 5 nm GaN at the same temperature and subsequent overgrowth with GaN at high temperatures resolves the In desorption problem and DBRs with improved interface quality and smooth surfaces are achieved. Optical properties of high reflectivity DBR structures such as maximum reflectivity and bandwidth are virtually unaffected whether or not unintentionally grown AIN interlayers are present. (C) 2014 Elsevier B.V. All rights reserved.