Theoretical analysis of triple junction field emission for a new type of cold cathode

Triple junction of metal-dielectric-vacuum is theoretically analysed. Electric field enhancement is observed in the vicinity of a metal-dielectric contact and considered to be due to the presence of dielectric. The dielectric enhancement in the problem gives rise to a new concept that dielectric can enhance the electric field, which is opposite to the usual view that dielectric reduces the electric field. This new type of enhancement is attributed to the polarization of dielectric. It is also found that the metal-dielectric-vacuum path is more favorable than the metal-vacuum path for field electrons. The present results suggest that the triple junction can be a new type of field emission source