Field emission property of carbon nanotube field emitters in triode structure fabricated with anodic aluminum oxide templates

In this work, we study the field emission (FE) properties of carbon nanotubes (CNTs) field emitters in the triode structure fabricated with anodic aluminum oxide (AAO) template. To obtain the self-consistent solution, a set of Maxwell's equations coupling with Lorentz equation are solved simultaneously using finite difference time domain (FDTD) particle-in-cell (PIC) method. The FE current is then computed with the Fowler-Nordheim equation. To validate our simulation model, we firstly calibrate the collected electron current density between the measurement data of fabricated AAO-CNTs and simulation result. We find that the high density of CNTs will result in large screening effect among adjacent emitters and reduce the strength of electric field. Consequently, it significantly affects the collected emission current density. Our prediction shows that more than three-order magnitude difference on the collected emission current density could be observed when the spacing between CNTs is decreased from 0.7 to 0.233 mu m for the explored structure with the diameter of 7 mu m. Effects of random heights and thickness of oxide on the FE property of structure are also discussed.