On relation between the autoemitter top field, anode voltage and cathode geometry

A field emission diode has been made up on the basis of a flat metal anode and pin cathode (of the height a) that is mounted on a flat metal plate parallel to the anode. The potential of the field emission diode has been calculated as the function of the pin cathode shape, its height, the anode-cathode potential and the potential value into cathode. It has been shown that the potential barrier transparency possesses a nonlinear dependence on the anode potential in the Fowler-Nordheim coordinates, if the cathode height (a) is less than 1000 nm. To obtain a measurable field emission current, the following condition should be met: Fmid · a>φ, were Fmid is the macroscopic field strength within the anode cathode spacing, and φ is the pin cathode work function. Therefore, to get the field emission current, either the field strength should be >106 V/cm, or another field source should be used in addition. For example, the contact electrode potential between the pin part of the cathode and its base can provide such a field source. An analytic function was derived for the electric field of a pin cathode located on a flat substrate