Electron Diffraction Based Analysis of Phase Fractions and Texture in Nanocrystalline Thin Films, Part II: Implementation

Abstract

AbstractThis series of articles describes a method that performs (semi)quantitative phase analysis for nanocrystalline transmission electron microscope samples from selected area electron diffraction (SAED) patterns. Volume fractions of phases and their textures are obtained separately in the method. First, the two-dimensional SAED pattern is converted into an X-ray diffraction–like one-dimensional distribution. Volume fractions of the nanocrystalline components are determined by fitting the spectral components, calculated for the previously identified phases with a priori known structures. Blackman correction is also applied to take into account dynamic effects for medium grain sizes. Peak shapes and experimental parameters (camera length, etc.) are refined during the fitting iterations. Parameter space is explored with the help of the Downhill-SIMPLEX algorithm. Part I presented the principles, while Part II now elaborates current implementation, and Part III will demonstrate its usage by examples. The method is implemented in a computer program that runs under the Windows operating system on IBM PC compatible machines.