A central aim of the present work is the application of nanofocused x-rays to the method of x-ray diffraction. Measurements have been performed by using a nanofocus setup at the European Synchrotron Radiation Source (France) with x-ray beams that were between 100 nm and 250 nm in size. Individual parts of a single SiGe island have been illuminated and distinct island ensembles as well as InGaAs quantum dot molecules were scanned. In case of InGaAs quantum dot molecules the nanodiffraction experiment has been accompanied by grazing incidence diffraction to analyze the in-plane strain. The diffraction patterns were interpreted and simulated using a new approach dedicated to scanning nanodiffraction which combines ?nite-element method and kinematical scattering with a beam pro?le. Information about shape, positional correlation and chemical composition of the low-dimensional structures was obtained, which also demonstrates the feasibility of the method of nanofocus x-ray diffraction.