Atomic-resolution quantitative composition analysis using scanning transmission electron microscopy Z-contrast experiments

Here a general approach to measure quantitatively with atomic resolution the distribution of a chemical species in a host matrix is derived and applied to a case study consisting of a layer of Si buried in a GaAs matrix. Simulations and experiments performed on SiGaAs superlattices demonstrate a quasilinear dependence of the high-angle annular dark-field image intensity on the concentration of Si in the GaAs matrix. The results have been compared with those obtained by cross-sectional scanning tunneling microscopy on the same specimens.