Strained and partially relaxed In1-xGa xAs yP1-y /InP single quantum wells (SQWs) with different cap layer thicknesses and biaxial strain values grown by low-pressure metalorganic vapor phase epitaxy (LP-MOVPE) were investigated by double crystal X-ray diffraction, photoluminescence microscopy (PLM) imaging and photoluminescence spectroscopy techniques. Our results indicate a significant improvement of the optical quality of the quaternary wells with increasing values of the cap layer thickness. Tensile and compressive strained In1-xGa xAs yP1-y /InP SQWs grown with the same structure exhibited different relaxation processes, even when the strain magnitude was the same. PLM images of highly compressive quantum wells exhibited a large number of dark lines corresponding to misfit dislocations as a result of the partial relaxation process in the well material. PLM images of similar tensile strained samples revealed only the presence of dark spots with no evidence of misfit dislocations.

We have observed changes in the morphology of InP films grown in epi-ready substrates and on patterns created by photo and plow-mode AFM lithography. These changes are attributed to different levels of contamination of the surface, which favor nucleation of clusters over a two-dimensional film for the lithography-processed surface. The area of nucleation is smaller than the dimensions of the patterns created by lithography, so no size effects due to the presence of the pattern could be observed. The film morphologies exhibited well defined exponents for system sizes smaller than 0.2 mum but no defined growth exponent.