Screening effects on field emission from arrays of (5,5) carbon nanotubes: Quantum-mechanical simulation

TL;DR

This study uses quantum simulations to analyze how array spacing affects field emission from carbon nanotubes, revealing optimal spacing and screening effects crucial for designing efficient emitters.

Contribution

It provides a quantum-mechanical analysis of screening effects and optimal spacing in carbon nanotube arrays for field emission applications.

Findings

Screening is strong when spacing is less than nanotube length.

Optimal spacing is two to three times the nanotube length.

Field enhancement decreases sharply with increased screening factor.

Abstract

The simulation of field electron emission from arrays of micrometer-long open-ended (5, 5) carbon nanotubes is performed in the framework of quantum theory of many electrons. It is found that the applied external field is strongly screened when the spacing distance is shorter than the length of the carbon nanotubes. The optimal spacing distance is two to three times of the nanotube length, slightly depending on the applied external fields. The electric screening can be described by a factor that is a exponential function of the ratio of the spacing distance to the length of the carbon nanotubes. For a given length, the field enhancement factor decreases sharply as the screening factor larger than 0.05. The simulation implies that the thickness of the array should be larger than a value but it does not help the emission much by increasing the thickness a great deal.