生长温度对碳纳米管阴极场发射性能的影响

Effects of CVD-Carbon Nanotubes Growth Temperatures on Field Emission Properties

碳纳米管（Carbon Nanotubes，CNTs）场发射平面显示器（Field Emission Display，FED）与其他显示器比较显示了其独特优点，被认为是未来理想的平面显示器之一。碳纳米管阴极作为器件的核心部分，其性能的好坏直接影响显示器的性能。针对30～60英寸（76．2—152．4cm）大屏幕显示器所用的厚膜工艺，即采用丝网印刷法制备了碳纳米管阴极阵列，研究了化学气相沉积法在不同温度下生长的CNTs的场发射电流-电压特性，找到了适合FED用碳纳米管的最佳生长温度。结果表明生长温度越高（750℃），CNTs场发射性能越好。并用荧光粉阳极测试这些CNTs的场发射发光显示效果，验证了上述结论。

Carbon nanotubes field emission display （CNTs-FED） has been regarded as the most promising flat work temperature range and low cost. As the key material, the properties of CNTs will affect FED characters directly. CNTs with good field emission properties were needed for the FED. The CNTs were synthesized by chemical vapour deposition （CVD） in the temperature range of 500 % -750 %. The morphologies of CNTs depending on growth temperatures were characterized by scanning electron microscope. ＂The as-grown CNTs were mixed with conductive pastes, then screen-printed on the glass substrate coated with a silver conducting layer to form a FED cathode. The dependence of FED properties on the CNTs growth temperatures was studied by using current-voltage （I-V） and luminescence image measurements. The SEM images shew that with the temperature increasing from 500℃ to 700℃, the average diameter of CNTs decreased. By the I-V and luminescence image measurements, it was found that the higher growth temperature, the better FED properties, i.e. lower turn-on emission field , higher emission current and more uniform emission. The field emission experiment of the CNTs cathodes indicated that there is an optimal temperature range （600 - 700 ~C ） for CNTs growth and being used as field emission cathode. With good properties, bright and stable anode image was observed in diode mode field emission. These results suggested that CVD grown CNTs could be used for cathode fabrication of large area field emission display.