Atomic-scale imaging of individual dopant atoms in a buried interface

Determining the atomic structure of internal interfaces in materials and devices is critical to understanding their functional properties. Interfacial doping is one promising technique for controlling interfacial properties at the atomic scale1-5, but it is still a major challenge to directly characterize individual dopant atoms within buried crystalline interfaces. Here, we demonstrate atomic-scale plan-view observation of a buried crystalline interface (an yttrium-doped alumina high-angle grain boundary) using aberration-corrected Z-contrast scanning transmission electron microscopy.