Molecular beam epitaxial growth of pseudomorphic InGaAs quantum wells on (100) GaAs substrates, patterned with vertical sidewalls using reactive ion etching, were studied. Contrary to the redshift observed in the photoluminescence from the ridges and grooves of patterned substrates with (n11) sidewalls, we have observed a blueshift in the case of vertical sidewalls. The possibilities of change in the strain tensor and the change in composition of the InGaAs grown in the grooves or on the ridges were considered in order to explain this increase in band gap. We believe that the vertical sidewalls act as kink sites for the migrating adatoms instead of sources, as in the case of (n11) sidewalls. We have demonstrated a blueshift of up to 50 meV without any degradation in the intensity and linewidth of the photoluminescence spectra.