Scanning transmission electron microscopy determination of critical InAs QD parameters from high-quality focused ion beam lamellas

InAs quantum dots in InGaAs matrix samples were prepared by focused ion beam (FIB) for cross-sectional scanning transmission electron microscopy (STEM) analyses in order to evaluate the quality of the FIB lamella preparation in the case of critical semiconducting materials. Despite the damage induced by the Ga ion bombardment, the good quality of the lamella led to a very accurate evaluation of important dot parameters, such as shape, size, In composition profiles in the dots and embedding matrix, from a direct analysis of the STEM images. These results were compared to those reported by the current literature for similar material systems, but often derived by indirect methods.