Role of the image forces potential in the formation of the potential barrier between closely spaced metals

The image forces potential Vj0(x) is shown to form a potential barrier in a small vacuum interval which is separated two half-limited media (two metals, two semiconductors or semiconductor and metal). It is found that the image forces potential Vcl0(x) obtained in the framework of local electrostatics in a vacuum interval between two semiconductors (dielectrics) depends on their static dielectric constants and differs appreciably from a case of two classic metals. It is shown that the account of the electronic structure of metals in the metal/vacuum/metal system provides a continuity of the image forces potential Vj0(x) on the interfaces and a common (vacuum) level for energy counting out and as well leads to slower increase of barrier height h(L), which is formed by the image forces potential, with the increasing the separated distance L, than in case of classic consideration.