Field emission stability of anodic aluminum oxide carbon nanotube field emitter in the triode structure

In this work, fabricated field emission (FE) triode arrays with the anodic aluminum oxide (AAO) template carbon nanotube (CNTs) as the field emitters are numerically analyzed. To obtain physically sound self-consistent solution, a set of Maxwell's equations coupling with Lorentz equation are solved simultaneously using a finite difference time domain particle-in-cell method. The FE current is then computed with the Fowler-Nordheim equation. To validate the simulation model, we firstly calibrate the collected electron current density between the measured AAO-CNT5 and calculated result. The FE current is dominated by, such as density, height, diameter, and tilt angle of CNT5, and applied bias, respectively. A high density of CNTs will result in strong screening effect among adjacent CNT5 and reduce the magnitude of electric field. Consequently, it significantly affects the emitted and collected electron current densities. However, the structure with much higher density of CNTs obviously emits more stable current than that of a low density of CNT5. There is an optimal setting on the height and diameter of the CNTs within the explored structure which exhibits the highest current density. When we vary the density of CNTs, the structure with high density (say the number of CNT5 is greater than 30) shows the most stable and smallest fluctuation on the current density against the randomly generated samples of the height and tilt angle of CNTs.