On the high accuracy lattice-parameters determination by n-beam diffraction: Theory and application to the InAs quantum dots grown over GaAs(001) substrate system

Ultra-precise lattice parameter measurements in single crystals are achievable, in principle, by X-ray multiple diffraction (XMD) experiments. Tiny sample misalignments have hindered the systematic usage of XMD in studies where accuracy is an important issue. In this work, theoretical basement and methods for correcting general misalignment errors are presented. As a practical demonstration, the induced strain of buried InAs quantum dots grown on GaAs (001) substrates is determined. Such a demonstration confirms the possibility to investigate epitaxial nanostructures via the strain field that they generate in the substrate crystalline lattice. This work was supported by the Brazilian founding agencies FAPESP (grant numbers 02/10185-3 and 02/10387-5), CNPq (proc. number 301617/95-3 and 150144/03-2) and LNLS (under proposal number D12A-XRD1 2490/03).