| Cathode ray tube (CRT) is a kind of display device with higher performance to price ratio. It is widely accepted due to its highest qualities on display color and imaging. However, CRT has some deficiencies, it is very heavy, own huge bodies, and need high power consumption. The flat panel display technology is the trend of the development. Field electron emission flat panel display is a very promising panel display technology, which not only possesses excellent display quality as CRT but also can make the flat panel come turn.The key point in technics of field emission display (FED) is to prepare field electron emission cold cathode with high efficiency, high stability and good uniformity. Many cathode materials have been studied, such as metal, diamond. The discovery of carbon nanotubes(CNTs) attracts many scientists' attention. CNTs can be used in many fields due to its excellent electricity, mechanics, magnetics function. Especially, it has a high slenderness ratio, low work function, good electrical conductivity and nanometer tip, which can emit electrons at low electric field. So CNTs is considered as a good field emission cathode. As field emission application, carbon nanotube has very high potential use and business value. And it has been used in electron beam device such as scanning electron microscope (SEM) and transmission electron microscope(TEM). It is believed that CNTs will have a wide application in flat panel display. Therefore, it is very meaningful to study the field electron emission properties of carbon nanotube.In this paper, field electron emission properties of carbon nanotubes are systematically researched and its main points are as follows:(1)The preparation and the measurements of field electron emission properties of carbon nanotubes films.Two kinds of carbon nanotubes-deposited films were prepared by electrophoretic and nanocomposite electrodepositing method. Field electron emission properties of the carbon nanotubes-deposited flexible film were measured by a diode assembly. The deposited film was used as a cathode, and a phosphorus coated indium tin oxide (ITO) glass as an anode. The two electrodes were separated by a 270μm spacer. The diode assembly was put into a vacuum chamber with a pressure of 5×10-5Pa. The field electron emission properties of the prepared thin films were tested by a diode assembly. The turn-on field of the film with electrophoretic method was about 1.6V/μm and current density was about 1mA/cm2 at an electric field of 3.7 V/μm, While turn-on field of the film made by nanocomposite electrodepositing method was about 2V/μm and current density was about 8μA/cm2 at an electric field of 3.7 V/μm. The experimental results indicate that this film prepared by electrophoretic method could be a promising material applicable to cold cathodes.(2)The optimization of experimental condition of CNTs film.By varying conditions such as electric voltage, electric current, temperature et al, different films were prepared. Results showed that when electric voltage was 150V, electric current was 60mA, duration was 90 seconds, the temperature was 60°C, and distance between two electrodes was 10mm, the best field electron emission properties with the method of electrophoretic deposition were obtained. |
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