Theoretical Study of Enhanced Field Emission at the Triple Junction

A cylindrical dielectric-metal structure is used to analyze the field enhancement due to an extension of the dielectric layer in a triple junction. Results show that this type of field enhancement is caused by the polarization of the dielectric and that it may take place along the detour path from metal through dielectric to vacuum instead of from metal to vacuum. The amount of space charge produced lowers and thins the metal-dielectric Schottky barrier allowing more electrons to tunnel from the metal to the conduction band of the dielectric. Results also suggest that the triple junction can be a new type of field emitter