Calculations of enhanced field electron emission at the triple junction

Numerical calculations of the field enhancement were carried out for a finite geometry of triple junction which consists of a half space of metal, a quarter space of dielectric and a quarter space of vacuum. The electric field F was analytically obtained as a function of geometry and dielectric constant. It was found that the enhancement factor is approximately 50 and 20 in the vacuum and the dielectric regions, respectively. It was also found that the metallic size and dielectric constant only determines the field intensity but not the enhancement of the field. Taking into account the space charge effect produced by strong field, the enhancement of field emission becomes larger.