Technique for Locating and Mapping the Surface Density of Micron-Sized Asperities Used as Cold-Cathode Elements

摘要

In order to understand the effects of field emission from asperities, it is necessary to make direct field-emission-current measurements of individual asperities. A procedural and evaluation technique has been refined using a modified Muller microscope with a motion resolution of 0.006 micrometers (60 A), which accurately determines the location and density of micron-sized asperities. The surface of a film of molybdenum metal containing asperities is scanned by means of a fine probe tip of positive potential with respect to the sample. The equipment is described and the technique used for locating individual asperities in order to give a field-emission contour of the metal surface is reviewed. Results on experimental samples are discussed; the criterion for the electric field strength of the asperities is discussed. (Author)