Physics of Carbon Nanotube Devices

Chapter 6. Field Emission

6.1. Introduction

Electron beams play a central role in many applications and basic research tools. For example, electron emission is used in cathode ray tubes, x-ray tubes, scanning electron microscopes, and transmission electron microscopes. In many of these applications, it is desirable to obtain a high density of narrow electron beams, with each beam tightly distributed in energy. So-called electron guns, which operate on thermionic emission of electrons from hot cathodes, are extensively utilized for this purpose. However, achieving electron beams with narrow energy distributions is difficult because of thermal broadening of the emitted electrons. Thus, field emission from cold cathodes is of much interest, but ...