Thin Film Carbon Nanotube Cathodes for Field Emission Flat Panel Display and Light Source Application

Abstract

The basic and applied aspects of field emission from carbon materials are considered in the example of thin film materials fabricated by using chemical vapor deposition in a plasma-activated hydrogen-methane gas mixture. The excellent field emission properties were found for the carbon films composed of nanostructured graphite-like material in the shape of nanotubes and nanocrystallites with the predominantly perpendicular orientation of their graphene sheets to the film surface. The threshold values of the macroscopic electric field are less than 1.5 V/mum,the emission current densities reach 100 mA/cm(2) and the emission site density is greater than 10(6) cm(-2). These properties are analyzed and discussed on the basis of the investigation of the film structure and electronic characteristics by using Raman spectroscopy, electron microscopy, cathodoluminescent technique, photoelectron, and secondary electron spectroscopy. The conclusion about the common nature of low-field electron emission from various carbon materials is made. The model of field emission site and the mechanism of field emission for nanostructured carbon are proposed. The device applicability of the carbon field cathodes is tested. The prototypes of the sealed diode fiat-panel display and the triode light source are presented.