Some aspects of field emission and field ion microscopy

Abstract

KEY WORDS Field emission, Atom probe and field ion microscope, Behavior of single atoms, Single atom chemical analysis, Depth profiles ABSTRACTThe field emission microscope can reveal the work function variation of an emitter surface with a spatial resolution of -25 A. It is particularly powerful for studying adsorption-desorption and surface diffusion phenomena. The field ion microscope can resolve single atoms on solid surfaces. Structures of deeper surface layers can be revealed by field evaporation. The chemical identity of surface atoms can be analyzed one by one by time-offlight mass spectrometry in the atom probe. Using these two instruments, behavior of single atoms on metal surface, compositional variations in the surface layers of alloys, and the atomic structures as well as compositional variations of various phases in alloys and materials can be studied with true single atomic layer, spatial resolution. Some aspects of field emission techniques and applications of them to surface science and material characterization are described here.