It is shown that the unusual scattering of the currently reported photoluminescence energy of GaInP/GaAs quantum wells (QWs) can be well accounted for by considering the combined effect of In surface segregation and As/P exchange at the interfaces. The resulting chemical modification of the interfaces being strongly growth procedure dependent, can explain the observed dispersion of the experimental results. This is demonstrated by experiments in which different growth switching procedures are used at the GaInP/GaAs QW interfaces. (C) 1997 American Institute of Physics. [S0003-6951(97)03450-5].