Visualising alloy fluctuations by spherical-aberration–corrected HRTEM
CNRS, CEMES ( Centre d'Elaboration des Matériaux et d'Etudes Structurales) - BP 94347, 29 rue J. Marvig, F-31055 Toulouse, France, EU
2 Université de Toulouse, UPS - F-31055 Toulouse, France, EU
Accepted: 23 July 2010
Under specific conditions of specimen thickness and experimental settings, aberration-corrected high-resolution transmission electron microscopy images of a SiGe alloy grown on a silicon substrate display strong intensity variation from one atomic column to the other. Combining TEM image processing, semi-empirical atomic simulations of large three-dimensional structures including the SiGe/Si interface and TEM image simulations, it is demonstrated that the observed contrast is strongly correlated to the Ge content in the different atomic columns. From a theoretical point of view, this reveals new possibilities for Cs-corrected transmission electron microscopy to observe chemical contrast, and more generally opens new routes for chemical mapping in nanoalloys.
PACS: 68.55.Nq – Composition and phase identification / 68.37.-d – Microscopy of surfaces, interfaces, and thin films / 68.37.Og – High-resolution transmission electron microscopy (HRTEM)
© EPLA, 2010