基于电场叠加原理,利用悬浮球模型给出了带栅极纳米管顶端电场与电场增强因子,分析了碳纳米管与衬底之间的接触电阻、器件几何参量以及阴栅极之间的电介质对器件场发射性能的影响. 结果表明：接触电阻大大降低了碳纳米管阴极的场发射电流,当接触电阻超过100 kΩ时,发射电流密度非常小,此时需要更高的阳极开启电压;当阴栅极之间的电介质为真空时,阴极电子发射性能最佳;除了碳纳米管的长径比之外,栅孔半径、阴栅极间距以及阳极距离等的优化设计,也能提高器件发射性能;通过栅极偏压的调制,可以降低阳极驱动电压.

The model of floated sphere in the triode configuration was proposed and the actual electric field and the field enhancement factor at the top of carbon nanotube were calculated analytically by superposition principle of electric field. The effects of the contact resistance, the geometrical parameters of device, and the dielectric of between the gate and cathode were computed. The calculation results show that the emission current from carbon nanotube is greatly reduced by the contact resistance. When the contact resistance is larger than 100 kΩ, the emission current from carbon nanotube tends to be zero. The field enhancement factor was at a maximum value under the condition of the vacuum. The gate-hole radius, the gate-cathode distance, and the gate-anode distance greatly affect the field emission properties of the device. The field emission properties improved via optimizing the parameters above mentioned and modulating the gate voltage.