| Abstract: | We describe a technique for efficient, quantitative, standardless elemental mapping using a high-angle annular detector in a scanning transmission electron microscope (STEM) to collect elastically scattered electrons. With a single crystal specimen, contrast due to thickness variations, diffraction, and channelling effects can be avoided, so that the resulting image contrast quantitatively reflects variations in impurity concentration. We compare a number of simple analytical approximations to the elastic scattering cross sections and show that a standardless analysis is possible over a wide range of atomic number and inner detector angle to an absolute accuracy of better than 20%. |
