Field emission characterization in a sphere plane diode configuration

The paper that we are going to present is about the characterization of field emission of a non-uniform distribution of emitters in a sphere-plane diode. In a recent article we showed that field emission in a non-uniform field can give information about the non-uniform distribution of emitters [1]. It can also explain the apparent non reproducibility of flat samples, which is a step toward standardization of field emission phenomena. In this follow-up paper we shall focus on an artificially generated non-uniform distribution that consists of various localized emission areas, much smaller than the diameter of the spherical anode. With our diode system we are scanning the anode over this area to verify our model of a single off-axis emitter. Applying a technique named Approach Curve Method (ACM) [2], for each position of the anode several I × V curves are generated as a function of the anode-sample distance (d). The V × d curves for a localized emitter distribution system enable a straightforward interpretation and will give information on the emitter position, the field enhancement factor (β) and the effective area of emission according to our model.