Investigation of GaInAs/InP superlattices by electron microscopy, x-ray diffraction and spectroscopic ellipsometry

Two sets of GaInAs/InP lattice-matched superlattices containing 30 periods, with a wide range of barrier and well thicknesses, were grown on (100) InP substrates by metal organic vapour phase epitaxy, using growth interruptions for interface optimization. Structural, compositional and optical characterization was performed by transmission electron microscopy, high-resolution x-ray diffraction and spectroscopic ellipsometry. The results from these complementary techniques agree quantitatively and show the good crystal quality of the samples. The interfaces in the long-period structures appear flat and sharp, while in the short-period ones they show undulations and graded-composition transition layers. A possible explanation for these effects is proposed.