有限元法分析栅极对CNTs场发射性能的影响

Study in the effects of normal-gate on the field emission properties of CNTs based on the finite element method

建立了栅极冷阴极结构和二极管结构的碳纳米管(CNTs)场发射阴极,利用有限元素法对发射体的场发射性能进行了模拟,进一步计算并分析了栅极、栅极电压以及栅孔半径等参数对碳纳米管尖端电场分布和场发射性能的影响.结果表明,栅极对碳管尖端的激发电场具有很强的增强作用;栅极电压越高,场增强因子越大;最佳场发射栅孔半径为碳纳米管半径的10倍;栅极使得碳纳米管的开启电压降低,发射电流密度增加.

The normal-gate cold cathode structure of the carbon nanotubes （CNTs） field emission cathode and diode structure have been established, and the field emission properties of CNTs have been simulated and calculated based on the finite element method. The effects of normal-gate, gate voltage and gate aperture on the distribution of the electric field near the tip of CNTs and field emission properties have been analyzed. The results indicate that the excited electric field has been strengthened by normal-gate. The variance ratio of emitted current density is increased by normal-gate. The field enhancement factor is increased with increae of gate voltage, and the optimal field emission performance can be obtained when gate aperture is 10 times of CNTs＇ diameter.