Carbon Nanotubes as a Pulsed Electron Sources

One of the most promising applications of carbon nanotubes (CNTs) is the emission electronics, in which CNTs are used as a field emission electron source. Lots of electronic devices are based on electron sources, which are the most important components served as state-of-art nanoelectronics devices in nowadays, such as field emission displays, miniature mass spectrometers, scanning ultrafast electron microscopes, X-ray generators, free electron lasers, THz sources, and so on. Field electron emission is based on the physical phenomenon of quantum tunneling, in which electrons are emitted from the surface of materials into vacuum on the condition of applied voltage. CNTs have many advantages as field emitters comparing with conventional metallic emitters like familiar examples of tungsten, gold, copper, and molybdenum. Electron emission from cold cathodes of CNTs has attracted attentions of numerous scientists, and substantial researches have been conducted on their properties and applications. In this chapter, we will focus on the field emission of CNT cold cathodes as an electron source, including of how to synthesize it by chemical vapor deposition (CVD) method and how to realize its electron emission. In addition, we will report pulsed electron emission of CNT cathodes. The combination of the laser pulse and the cold cathode will offer the possibility of pulsed field emission. Our approach demonstrates the growth mechanism and the emission mechanism of CNTs, which is beneficial for controlling the performance of its fascinating application on emerging fields