Optical and structural characterization of LP MOVPE grown lattice matched InGaP/GaAs heterostructures

Lattice matched InGaP alloys grown by Low Pressure Metal Organic Vapor Phase Epitaxy were studied by Atomic Force Microscopy, X-ray diffraction, microRaman spectroscopy and Photoluminescence mapping. The study is devoted to the analysis of both the composition fluctuations and spontaneous CuPt-type order. N-type (Si-doped) and semi-insulating substrates were used. Order seems to occur in a higher amount in layers grown on Si-doped substrates; the morphology and the properties of the layers are shown to depend on the type of substrate. The Raman study of the layers allows to establish the influence of CuPt-type order on the Raman spectrum of lattice matched InGaP. The relation between the Raman parameters and the spontaneous CuPt-type order is discussed.