Atomic‐Precision Manipulation of Defects in RuO₂ Nanocrystals via Electron‐Beam

Abstract Manufacturing nanocrystals with desired structures is the basis for realizing designed properties in their applications. As an important top‐down fabrication technique, although electron beam (e‐beam) has been well used for atomic etching on one hand, it is still challenging to precisely repair the undesired crystal defects on the other. Herein, utilizing the e‐beam probe in a spherical aberration‐corrected scanning transmission electron microscope, the possibility of e‐beam in the atomic‐level‐controllable construction/repair of crystalline defects in ruthenium oxide (RuO 2 ) nanocrystals is systematically explored. It is found that the functional duality of beam effects can be well controlled, with the domination of either constructing or repairing defects in atomic scale, by tuning e‐beam parameters. With the aid of real‐time observation of the atom‐by‐atom repairing process via in situ scanning transmission electron microscopy and density functional theory calculations, the e‐beam‐assisted repairing mechanism is revealed. This work is anticipated to provide insights into controllable top‐down manufacturing nanomaterials at the sub‐nanoscale by e‐beam.