Substrate nanoprotrusions and their effect on field electron emission from amorphous-diamond films

Abstract

Geometrical field-enhancement structures at the surface of a substrate have been expected to effectively lower fields required to inject electrons from the substrate into amorphous-diamond (a-D) films. Two techniques have been developed to create a high density of nanoprotrusions on substrate surfaces: (a) on silicon (Si) substrates using our patented chemical-etching technique, and (b) on aluminum (Al) film by following a special deposition procedure. The density of nanoprotrusions can be as high as 108/cm2, and the mean roughness of the substrates is 2–30 nm. From a-D emitters, substrate surfaces with such nanoprotrusions can lower the field for emission. The results are discussed in light of several existing theoretical models.