Structuring single- and nano-crystalline diamond cones

A novel method of nanostructuring diamond films into cone arrays through bias assisted reactive ion etching (RIE) is reported. It can be applied for both micro-crystalline diamond, forming single-crystalline cones and for nanodiamond films, forming nanodiamond cones. The density and the geometry of the cones are controlled by the initial texture of the diamond films and by the RIE conditions. Pyramidal [0 0 1]-textured films yield very sharp single-crystalline cones with the [0 0 1] axis perpendicular to the substrate surface, an apical angle of approximately 28degrees and a tip radius as small as 2 nm. Cones made of nanodiamonds with a similar apical angle of 28degrees and a variety of densities and sizes can be structured from nanodiamond films. A possible application is field electron emission (FEE), which is significantly improved in nanostructured cone arrays of all types of diamond films. The FEE of nanodiamond cone arrays is better than that of single-crystalline cone arrays of diamond with a similar density and geometry. (C) 2003 Elsevier B.V. All rights reserved.