Dielectric effect on electric fields in the vicinity of the metal–vacuum–dielectric junction

• Published in: Ultramicroscopy 2013-09, Vol.132, p.41-47
• Main Authors: Chung, M.S., Mayer, A., Miskovsky, N.M., Weiss, B.L., Cutler, P.H.
• Format: Article
• Language: English
• Subjects: Dielectric effect; Field enhancement; Metal–dielectric contact; Triple junction
• ISSN: 0304-3991; 1879-2723
• DOI: 10.1016/j.ultramic.2012.12.014

The dielectric effect was theoretically investigated in order to describe the electric field in the vicinity of a junction of a metal, dielectric, and vacuum. The assumption of two-dimensional symmetry of the junction leads to a simple analytic form and to a systematic numerical calculation for the field. The electric field obtained for the triple junction was found to be enhanced or reduced according to a certain criterion determined by the contact angles and dielectric constant. Further numerical calculations of the dielectric effect show that an electric field can experience a larger enhancement or reduction for a quadruple junction than that achieved for the triple junction. It was also found that even though it changes slowly in comparison with the shape effect, the dielectric effect was noticeably large over the entire range of the shape change. ► This work explains how a very strong electric field can be produced due to the dielectric in the vicinity of metal–dielectric contact. ► This work deals with configurations which enhance electric fields using the dielectric effect. The configuration is a type of junction at which metal, vacuum and dielectric meet. ► This work suggests the criterion to determine whether field enhancement occurs or not in the triple junction of metal, vacuum and dielectric. ► This work suggests that a quadruple junction is more effective in enhancing the electric field than a triple junction. The quadruple junction is formed by an additional vacuum portion to the triple junction. ► This work suggests that a triple junction can be a breakthrough candidate for a cold electron source.