(In,Ga)As/GaAs quantum wells were heterogeneously integrated on planar and patterned Ge/Si (001) substrates by molecular beam epitaxy. Both nominal and vicinal substrates were employed. Structural characterization was done by scanning electron microscopy, scanning transmission electron microscopy and X-ray diffraction. We compare the photoluminescence (PL) of the (In,Ga)As/GaAs quantum wells on these different substrates. For nominal and patterned substrates, the PL is observed to deviate from the transition wavelengths derived from simulations. Scanning electron micrographs reveal causes of these deviations. For growth on planar vicinal substrates, we can clearly assign the PL peaks to interband transitions derived from simulations. (c) 2013 Elsevier B.V. All rights reserved.