Preparation And Field Emission Properties Of Amorphous Carbon Film

Display is an device intermedium of people and machines. It can be considered as a bridge between them. Much information can be passed by vision to people via displays from every machine or furnishment.Flat panel display is becoming more attracting as a kind of new display technology. Compared to CRT, it has advantages such as low weight, small volume and low power consumption. Therefore, it has been widely used in many fields such as large screen display and handy computers. Field emission flat panel display is a new display technology and has been a focus in recent years. The key point in technics of field emission display(FED) is to prepare field emission array(FEA) with high efficiency, high stability and good uniformity. Many cathode materials have been studied, such as metal spindt FEA, carbon nanotubes and so on. There are relatively a few reports about amorphous carbon film as cathode in FED. Because of its good chemical inertness, thermal stability, high melting point, high thermal conduction coefficient, small dielectric constant, large carriers transition velocity and high breakdown voltage, especially its low electron affinity(EA) or negative electron affinity(NEA), amorphous carbon film as cathode material has become an important orient in research.In this paper, field emission properties of amorphous carbon films are systematically studied and its main points are as follows:(1) the preparation and the measurement of field emission properties of nano-structured amorphous carbon filmsSi(111) slices being rubbed by CW powders were used as substrates, on which amorphous carbon films were prepared by microwave plasma chemical vapor deposition(MPCVD). Surface morphology and microstructure of films were tested by SEM, XRD, Raman Spectroscopy and XPS. A diode structure was used in field emission measurement under a certain vacuum condition(< 5 × 10^-5Pa) and field emission spots were recorded by CCD through anode coated with phosphors. Results showed that the prepared nano-structured amorphous carbon film had better field emission properties,with low turn-on field of 0.6V/^m, high current density of 2.5 mA/cm2( at 3.7 W/fim ), high emission stites density of 105 /cm2.(2) the optimization of experimental condition of nano-structured amorphous carbon filmo Results showed that when the intergrate layer is Ti, CH4 flow rate equals to 16 seem, micro wave power is 1700 watt,the best field emission properties were obtained.(3) As an application of nano-structured amorphous carbon film, field emitters,cathode-ray tube (CRT) type lighting-elements were manufactured. In this display element,conventional thermionic cathode was replaced by ht cold cathode of nano-structured amorphous carbon film. Stable electron emission,adequate luminance was demonstrated.