Introduction: Functions and Performances Governed by the Work Function

Abstract

This chapter explains why work function is important and how work function influences properties and performance of various devices in broad fields of applications. The importance and influences are described by dividing into two categories: electron emission into vacuum from a solid, and electron ejection into a solid from another solid across the interface between the two solids. Phenomena of electron emission into vacuum are used to generate electron beam, which is applied in many apparatuses such as electron microscope, electron lithography, synchrotron radiation photon sources, and colliders for nuclear physics research. Electron emission phenomenon is also used to initiate electric discharge for plasma generation, whose application ranges from industrial applications such as film deposition to neon signs. The second category, electron ejection into a solid (not a vacuum) is an electron transfer between the two solids, and a basis of most electronic devices. It is well known that the ideal Schottky barrier height at a metal–semiconductor interface is determined by the work function of the metal and the electron affinity of the semiconductor. Schottky barrier height is important for the efficiency of light emitting devices and solar cells. The contents of the following chapters and the relationship between the chapters is summarized at the end of this chapter.