X-Ray diffraction analysis of multilayer InAs-GaAs heterostructures with InAs quantum dots

Multilayer InAs-GaAs structures with an array of vertically aligned InAs qu antum dots in a GaAs matrix, grown by molecular-beam epitaxy, were investig ated by crystal truncation rods and high-resolution x-ray diffractometry me thods. It was shown that the formation of scattering objects such as vertic ally aligned quantum dots in the structures strongly influences the mechani sm of diffraction scattering of x-rays and changes the spatial distribution of the diffracted radiation. This is explained by the appearance of additi onal long-range order in the lateral arrangement of the scattering objects in the periodic structures, by the curving of the crystallographic planes i n the periodic part of the structure, and by the quasiperiodicity of the de formation profile due to the vertically coupled quantum dots. The observed spatial distribution of the diffracted intensity can be explained qualitati vely on the basis of a new model where the scattering layers with quantum d ots consist of defect-free, coherently coupled, InAs and GaAs clusters. (C) 1999 American Institute of Physics. [S1063-7826(99)01711-1].