Extracting scaled barrier field from experiments with conducting large-area field emitters: Considerations by inclusion of the dependence between area of emission and the applied field

With a large-area field electron emitter (LAFE), the area of emission is expected to be dependent of the applied field. One possible explanation for this behavior is the statistical distribution of the local field enhancement factors (FEFs), as a consequence of an irregular surface's morphology of the LAFE. In this paper, the authors present a simple and more general theory for extracting the scaled barrier field, f, by considering the dependence of the formal area of emission of conducting LAFEs with an applied field. In our model, the local FEFs of LAFE sites are exponentially distributed, which is consistent with thin film electron emitters. As a byproduct of technological relevance, our results show that general effective f values extracted from linear Fowler–Nordheim plots are outside of the “experimentally reasonable” range of values for physically orthodox emission, when the area of emission varies significantly with the applied field. Thus, a more general criterion for detecting and interpreting nonorthodox field emission is proposed and can be applied to any distribution of local FEFs in conducting LAFEs.