Atom-by-atom fabrication with electron beams

Assembling matter atom-by-atom into functional devices is the ultimate goal of nanotechnology. The possibility of achieving this goal is intrinsically dependent on the ability to visualize matter at the atomic level, induce and control atomic-scale motion, facilitate and direct chemical reactions, and coordinate and guide fabrication processes towards desired structures atom-by-atom. In this Perspective, we summarize recent progress in chemical transformations, material alterations and atomic dynamics studies enabled by the converged, atomic-sized electron beam of an aberration-corrected scanning transmission electron microscope. We discuss how such top-down observations have led to the concept of controllable, beam-induced processes and then of bottom-up, atom-by-atom assembly via electron-beam control. The progress in this field, from electron-beam-induced material transformations to atomically precise doping and multi-atom assembly, is reviewed, as are the associated engineering, theoretical and big-data challenges.