Field enhancement for fiber emitters in linear and rectangular arrays

One of the key issues for understanding the emission physics of field emitters is the determination of the field enhancement factor β. Quantifying β is complicated by determining accurate values for the work function and emission area. In this article, the authors consider two and four carbon fiber emitters in linear and square arrays in which the geometry, hence β, can be carefully controlled, while computational methods allow an estimate of the emission area. In order to reduce the effects of work function variation between different fibers, all the carbon fiber cathodes the authors use are made with the same materials and underwent the same manufacturing process. This approach reduces the influence of work function and emission area on experimental results. While single emitter tips and large arrays of emitters (∼1000 s) have been studied in the past, this article addresses the emission of low numbers (<10) of field emitters in carefully controlled geometries. Studying such configurations allows us to develop a model that leads to greater physical insight for β and the emission process.