Three-dimensional self-ordering in an InGaAs/GaAs multilayered quantum dot structure investigated by x-ray diffuse scattering

摘要

X-ray diffuse scattering from a 17-fold InGaAs/GaAs quantum dot (QD) multilayer grown by an advanced molecular beam epitaxy process was investigated. The QDs in each layer form extended chains that are oriented along the [110] planar direction. A prominent three-dimensional satellite structure in the x-ray diffuse scattering is found, which is caused by a strong lateral chain-chain correlation and vertical correlation of the lateral chain positions in the multilayer. In contrast, the dot-dot correlation within the chains are comparatively small. Numerical x-ray scattering simulations have been carried out. A comparison with corresponding experimental intensity patterns provides information on the QD size and QD spatial distribution.