Field electron emission from tungsten micro-tips coated with various thicknesses of polystyrene nanolayers: Characteristics & analysis

Abstract

This paper studies and analyses the characteristics of cold field electron emission from uncoated polycrystalline tungsten tips before and after being coated with an insulating polystyrene layer of different thicknesses. The process of testing the samples has been carried out under high vacuum conditions (10−8 mbar). Uncoated tungsten tips were prepared using the electrochemical etching process. The current-voltage characteristics of the samples before and after being coated were presented and analysed using Murphy-Good plots. Scanning electron micrographs for the samples under investigation have been included. Additionally, the electron emission patterns, before and after the coating process have been included. This is to compare the obtained results and study the effect of the coating layer on the performance of the electron source. The results show significant improvements on the performance of the coated tungsten emitters in comparison with the uncoated emitters.