InAs/GaAs quantum dots morphology: Nanometric scale HAADF simulations

A quantitative methodology of In distribution in nominal InAs/GaAs individual quantum dot (QD) is presented. Numerical simulations, using multislice-based approach, allow predicting high angle annular dark field (HAADF or Z-contrast) micrograph contrasts working in scanning transmission electron microscopy (STEM) mode. Even the method is adapted for nanometric scale; it is shown that its high sensitivity can reveal In-segregation in QD. The here observed samples show In diffusion below the wetting layer giving an elliptical-like shape of the observed QD.