We report on the growth and characterization of InAlGaN films and InGaN/InAlGaN MQW structures by metalorganic vapor phase epitaxy (MOVPE). The composition of the grown films was evaluated by high-resolution X-ray diffraction (HRXRD) and secondary ion mass spectrometry (SIMS) measurements. It was found that increasing the In precursor flow not only increased the In content of the InAlGaN films but also decreased the Al content. Uniform compositional depth profile was achieved when the In content of the films was below 0.02. At higher In contents the InAlGaN/GaN interface became diffused. In the InGaN/InAlGaN MQW samples increasing the In content of the barrier layers to 0.016 was found to cause non-uniform distribution of Al and degrade the optical quality of the samples. (c) 2007 Elsevier B.V. All rights reserved.