Vertical alignment of multilayered quantum dots studied by x-ray grazing-incidence diffraction

The degree of vertical alignment of multilayered Ge/Si(100) quantum dots has been investigated. We present a general analytical model for the analysis of lateral deviations in vertically stacked quantum dots based on the evaluation of the superlattice Bragg sheets. The width of the Bragg sheets is found to increase quadratically with lateral momentum transfer, which is in agreement with the theoretical prediction of our model. A mean stacking fault can be derived from the experimental data.