We report on the growth of InN/GaN quantum well structures via metal organic vapour-phase epitaxy. From X-ray diffraction and transmission electron microscopy measurements we find that at 530 C, the temperature optimal for InN growth, the duality of the GaN barriers is too poor and quantum well formation is not observed. However, InN quantum wells can be grown at a higher temperature of 570 C, although with rough interfaces and evidence of In segregation. Though photoluminescence is obtained from all samples, no evidence of quantum size effects is seen. (C) 2008 Elsevier B.V. All rights reserved.