Evaluation of numerical characteristics of the current load distribution on the surface of multi-tip field emitters

The uniformity of the emission sites distribution over the surface of the multi-tip field emitter is one of the main factors affecting its electrical characteristics. Increase of the uniformity leads to increase of the thermal stability and allowable current limit. The paper describes an experimental setup and a method for monitoring uniformity of the emission sites based on analysis of a field emission site images registered on the phosphor screen of a computerized field-emission projector. The analysis includes estimation of the statistical distributions of the sites by radius, by angle and by intensity, as well as the distribution of the current load over the emitter surface. The technique was tested with the perspective nanocomposite cathode MWCNT / polystyrene.