模拟研究常闭和常开工作模式下的平面栅极型碳纳米管场发射电子源

采用数值模拟的方法对比性地研究了常闭和常开工作模式下平面栅极型碳纳米管场发射电子源.静电场的数值计算结果显示:常闭工作模式下该电子源中阴极电极的表面电场分布不均匀,边缘处的高电场易导致其上的碳纳米管烧毁,从而引起场发射电流衰减.为了解决此问题,提出将常开工作模式用于该电子源,并证实常开工作模式能够用于该电子源,并有利于解决电流衰减问题.因此,相对于常闭工作模式,常开工作模式更适合平面栅极型碳纳米管场发射电子源.

Simulation of Planar Gate-Type Carbon Nanotube Field Emission Electron Source in Normally-off and Normally-on Modes

The planar gate-type carbon nano-tube field emission electron sources operating in normally-off and normally-on modes were simulated in finite element method.The electric field distributions of the system were numerically calculated.The simulated results show that when the electron source works in normally-off operation modes,its field emission current gradually decays because the high electric field at the edges of the cathode often leads to burning of the carbon nanotubes.However,the normally-on operation mode can be an effective solution to the problem of current degradation on the basis of our simulation.We propose that the normally-on operation mode be more suitable than the normally-off operation mode for the planar gate-type carbon nano-tube field emission electron source.