Effect of molecules adsorbed on the cathode surface on the prebreakdown field-emission current at the initial stage of a high-voltage gas discharge

Formulas for calculating the prebreakdown current density are derived taking into account the present of clusters of adsorbed atoms, polar and nonpolar molecules, as well as nanofilms on the cathode surface. It is shown that the expression for the current-voltage characteristic is an analog of the Fowler-Nordheim equation in all cases. The presence of a thin nonmetallic film necessitates the replacement of the Nordheim function by any tabulated function that can also be expressed in terms of elliptic integrals. If the degree of coating is smaller than unity, corrections should be introduced into the expression for the work function.