High-speed scanning tunneling microscope technique and its application in studying structural dynamics on surfaces

The study of processes concerning adsorption, diffusion and reaction of atoms and molecules on surfaces is one of the core areas of surface science research. Resolving these dynamic processes with atomic resolution in real space and at real time is of great significance for the understanding of catalytic reaction mechanism and the development of new materials. A scanning tunneling microscope with fast imaging function, a so-called “high-speed scanning tunneling microscope” combining both high temporal and high spatial resolution, is an ideal instrument to characterize processes within this area. This review aims to highlight some recent developments of high-speed scanning tunneling microscope technique and its application to study the structural dynamics on surfaces. Firstly, factors that limit the time resolution of scanning tunneling microscope are analyzed from the aspects of both hardware and software. Secondly, strategies and instrument designs enabling imaging rate up to 100 frames per second are introduced. Then, recent breakthroughs on resolving surface structural dynamics, such as atom diffusion, on-surface synthesis of low-dimensional materials and chemical reaction, by high-speed scanning tunneling microscope are highlighted. Finally, the challenges and opportunities of high-speed scanning tunneling microscope technique are outlined and a perspective is provided.