Anisotropic etching of diamond by molten Ni particles

Abstract

Nanopores in insulating solid state membranes have recently attracted much interest in the field of probing, characterizing, and manipulating single linear polymers such as DNA/RNA and proteins in their native environment. Here a low cost, fast, and effective way to produce nanostructures such as pyramidal shaped nanopores and nanochannels with dimensions down to about 15 nm in diamond membranes without any need for electron-beam lithography is demonstrated. By use of a catalytic process, anisotropic etching of diamond with self-organized Ni nanoparticles in hydrogen atmosphere at 900 degrees C is achieved and possible etching mechanisms are discussed. It is shown that diamond planes with the crystallographic orientation of [111] are etched slowest with this method

Formation of oriented nanostructures in diamond using metallic nanoparticles

“…It has been shown that Ni-assisted diamond etching is slowest for the [111]-oriented diamond planes and that they act as stopping planes [13]. Since the uptake of carbon atoms from diamond by the metal nanoparticles occurs from the weakly bonded atoms, the carbon atoms of the closest packing plane, the {111} planes, are the most stable against the dissolution of carbon in nanoparticles, as compared to the other crystal planes [30].…”

“…The orientation dependence of diamond etching has been studied before using molten Ce [28], Fe particles [29], Co nanoparticles [30], and molten Ni [13], as catalysts. It has been shown that Ni-assisted diamond etching is slowest for the [111]-oriented diamond planes and that they act as stopping planes [13].…”

“…However, in the case of sensors based on nanopores in a membrane [10][11][12], this etching technique fails to create narrow (10-50 nm in diameter) and long (typically longer than 300 nm) holes in the diamond membrane due to the limitation of lithographic resolution. Based on reported works [13,14] on catalytic etching of diamond, we have developed a fast and simple etching method through the catalytic gasification of carbon by metallic nanoparticles in a hydrogen atmosphere. In this process, the etching of diamond proceeds with: (1) the formation of nanoparticles from the initially deposited metal film, (2) the carbon dissolution into nanoparticles through the breaking of crystallinity at the diamond-metal interface [15][16][17] and, finally, (3) the desorption of carbon with the assistance of a hydrogen atmosphere.…”

“…We emphasized the etching of [100]-oriented diamond planes, since it is shown that metal-assisted diamond etching is slowest for [111]-oriented planes and that they act as stopping planes [13].…”

Diamond Ultramicro- and Nano-electrode Arrays

“…To produce boron-doped diamond based structures, reactive ion etching of the wafer (Fig. 9.2d) is conducted in a gas mixture of oxygen and hydrogen [58]. Please note that these structures are protected.…”