Transmission electron microscopy and photoluminescence investigations have been carried out on a series of quantum wells grown by molecular beam epitaxy and metal organic vapour phase epitaxy. In both cases, the emission wavelength and the peak width agree with the indium local composition as extracted from strain measurements and with the well width. As could be expected, the data is at small variance with the nominal values as set during growth, but the general trends are similar. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim