Structural Characterization of InAlAs/InGaAs Layers Grown on InP Patterned Substrates

ABSTRACTIn this work we present structural characterization by both Scanning and Transmission Electron Microscopy of InAlAs/InGaAs heterostructures grown on InP substrates. Our attention is devoted to study the two main problems limiting the application of these structures as devices: the presence of defects on the epilayer and the growth habit at theedges of the well. Our results show that a different faceting between the two <110> orthogonal directions develops during the growth and that a high density of defects is observed just at the intersection between the layers grown inside the windows and on the walls. Moreover, the presence of a polycrystalline layer developing over the mask indicates that a selective growth occurs.