Fast-scanning STM studies

Dynamic processes on surfaces play a crucial role in important areas such as catalysis, thin-film growth, and sensor technology. With the advent of scanning tunneling microscopy (STM) in the 1980s, scientists could visualize these processes in real space. This has led to unprecedented new insight into, for example, diffusion, reaction, nucleation, and growth phenomena on surfaces at the atomic level, strongly improving the basis for surface engineering in materials science. An imperative for visualizing dynamic phenomena on surfaces is the ability to acquire adequate temporal resolution, i.e. to record STM images at a sufficiently high rate. In this article, we illustrate, primarily with examples from our own laboratory, how fast-scanning STM can be applied successfully to studies of dynamic processes on surfaces, in particular (a) mass transportation induced by adsorption, (b) diffusion of adatoms on surfaces, (c) diffusion of vacancies on TiO2, and (d) the influence of molecular orientation on diffusion properties.