Direct Imaging of Single Dopant Atoms in a Buried Crystalline Interface by Scanning Transmission Electron Microscopy

Abstract

Aberration-corrected scanning transmission electron microscopy is becoming a very powerful tool to directly image dopant atoms within buried crystalline interfaces. Here, we demonstrate direct imaging of individual dopant atoms in an alumina interface. The focused electron beam transmitted through the off-axis crystals clearly highlights the individual yttrium atoms located on the monoatomic layer interface plane. Not only is their unique two-dimensional ordered positioning directly revealed with atomic precision, but local disordering at the single atom level, which has never been detected by the conventional approaches, is also uncovered. The ability to directly probe individual atoms within buried interface structures will be powerful for characterizing internal interfaces in many advanced materials and devices.