The growth and the characterization of AlxIn1-xN/GaN (x > 0.75) heterostructures by migration-enhanced metal-organic chemical vapor deposition are optimized through variations in growth temperature and precursor modulation schemes, resulting in high quality films. AlxIn1-xN/GaN heterostructures were characterized by XRD reciprocal space mapping in order to calculate the relative strain to GaN as a function of indium composition. AFM measurements yielded an rms roughness value of similar to 4 angstrom. By controlling indium incorporation, a maximum 2DEG mobility of similar to 1270 cm(2)/V s, a maximum sheet charge density of similar to 4.1 x 10(13) cm(-2), and a minimum sheet resistance of 179.9 Omega/square were obtained. (C) 2011 Elsevier B.V. All rights reserved.