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.

将物质逐个原子地组装到功能设备中是纳米技术的最终目标。实现此目标的可能性本质上取决于在原子级上可视化物质，诱导和控制原子级运动，促进和指导化学反应以及协调和引导制造过程逐原子进行的能力。在本《观点》中，我们总结了像差校正扫描透射电子显微镜的会聚，原子大小的电子束在化学转变，材料变化和原子动力学研究方面的最新进展。我们讨论了这种自上而下的观察如何导致可控的束诱导过程的概念，然后导致通过电子束控制实现自底向上的逐个原子组装的概念。在这个领域的进展，