Simulation of electron diffraction patterns from III–V alloys with CuPt ordering : Effect of clusters and antiphase boundaries

• A method for the simulation of electron diffraction patterns from partially ordered semiconductor compounds with CuPt-type ordering is proposed. The simulation procedure is based on the generation of two-dimensional model structures containing different types of imperfections. The defects are randomly dispersed in the structure and they are characterized by statistical parameters (density, average size, shape, etc.). Performing the intensity calculations for electron diffraction, the influence of the selected types of defects on the diffuse scattering in the transmission electron microscopy (TEM) diffraction patterns can be analyzed and the correlation between the statistical parameters describing the defects and the fine structure of the diffuse scattering can be established. By means of this method the influence of the plate-like clusters and of the antiphase boundaries (APBs) on the TEM diffraction pattern is analyzed. It is shown that the slope of the diffuse streaks around the ordering diffraction spots is determined by the mean orientation of the cluster boundaries irrespective of the type of clusters. The role of the fine structure of the inclined APBs in the formation of the diffraction patterns is established. (C) 2001 American Institute of Physics.

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NATURVETENSKAP  -- Kemi -- Oorganisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Inorganic Chemistry (hsv//eng)

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