Abstract
We have examined the structure of InGaAs and InAlAs strained monolayers grown by Molecular Beam Epitaxy on (111)B 1° off toward [211] InP substrates. Transmission Electron Microscopy and Atomic Force Microscopy observations have revealed the bunching of InAlAs surface steps. The film exhibits structural inhomogeneities and threading dislocations induced by the coalescence of misorientation steps. The characterizations performed on the InGaAs film have shown periodical contrasted domains developing in the direction of growth. From similar results obtained on InP(100)-based growth, we have interpreted these variations to be composition modulation involved in the tensile strains relaxation process. Also, InAs epitaxy performed on the InAlAs top-surface has demonstrated that the first stage of growth were proceeding at the bunched step edges following a 3D mechanism.