The dynamical theory as developed by Takagi and Taupin for imperfect crystals has been applied to analyse the intensity distribution of the superlattice diffraction peaks, and to compute the rocking curves when the interface grading and the period thickness fluctuation are present. The reason why the interference fringes between the superlattice diffraction peaks disappear and the superlattice diffraction peaks broaden are discussed. It is clear that the intensity distribution of the superlattice diffraction peaks depends on the superlattice period thickness, the composition and strain in it. The interface gradient and the period thickness fluctuation may affect the double-crystal rocking curves. The main reason of the superlattice diffraction peak broadening is the bending of lattice plane.
下载:
