Maximizing the electron field emission performance of carbon nanotube arrays

The field emission screening effect is one of great importance when aiming to design efficient and powerful cathodes. It has long been assumed that the degrading effect is at a minimum when neighboring emitters are at least twice their height from each other. In this work, we show that the screening effect is underestimated and diminishes at far greater separations of five times the height of the emitter. We further observe that to achieve maximum emission efficiency in an array, one requires a trade off between screening and emitter number, resulting in a separation of three times their height.