Fibrous structures on diamond and carbon surfaces formed by hydrogen plasma under direct-current bias and field electron-emission properties

Abstract

Polycrystalline diamond films, single crystal bulk diamonds, and diamond powder were treated in microwave plasma of hydrogen at 1.6 torr under a negative direct-current bias of −150 to −300 V without metal catalyst. It was found that fibrous structures, uniformly elongated along the direction normal to the specimen surface, were formed on the diamond surfaces. Similar experiments for glasslike carbon resulted in conical structures with frizzy fibers at the tops. Transmission electron microscopy measurements indicated that the fibers formed on diamond consisted of randomly oriented diamond nanocrystals with diameters of less than 10 nm, while the conical structures formed on glasslike carbon consisted of graphite nanocrystals. Field emission measurements of the fibrous specimens exhibited better emission efficiency than untreated ones. The field emission electron microscopy of the fibrous glasslike carbon showed a presence of discrete electron emission sites at a density of approximately 10,000 sites/cm2.

Vertically aligned diamond nanowires: Fabrication, characterization, and application for DNA sensing

“…On nanostructured surfaces, the electric field concentrates at tips of wires which stimulate current flowing preferentially through wires and their tips. Therefore, this will lead to preferential bonding of nitrophenyl to the tips of wires, giving rise to preferential modifications of nanowire tips 10. For biosensor applications, a wire separation distance of 10 nm has been selected since it will result in a DNA density of about 10 12 cm −2 if these wires are used for anchoring DNA molecules.…”

“…Later in 2000, nanostructured honeycomb films were prepared by etching diamond through a porous anodic alumina mask 9. Growth induced formation of nanoscaled tubular structures have been reported for the first time in 2003 via application of hydrogen microwave plasmas in combination with DC bias potentials 10. In 2008, Zou et al 11 reported the fabrication of nanopillar arrays using self‐aligned Au nanoparticles as the etching mask in a bias‐assisted RIE system by application of hydrogen/argon plasmas.…”

Diamond nano-wires, a new approach towards next generation electrochemical gene sensor platforms

“…Later in 2000, nanostructured diamond honeycomb films have been prepared [31] by etching through a porous anodic alumina mask, triggering some activities which are summarized in an article of Shenderova et al [32] Growth induced formation of nano-scale tubular structures have been reported for the first time in 2003, applying a microwave plasma of hydrogen under a bias potential. [33] In 2008, Zou et al [34] reported about the fabrication of nanopilar arrays using self aligned Au nanodots as etching mask in a bias-assisted reactive ion etching, applying a hydrogen/argon plasma. Although these achievements demonstrate that vertically aligned diamond nano-wires can be fabricated by a variety of methods, no applications in electro-or bio-chemistry have up to now been reported.…”

Vertically Aligned Diamond Nanowires for DNA Sensing

“…Diamond varies from an insulating, to semiconducting, to metal-like conducting materials with increasing doping levels. [8] In 2008, Zou et al [9] reported the fabrication of nanopillar arrays using self-aligned Au nanodots as an etching mask in bias-assisted reactive ion etching with a hydrogen/argon plasma. Diamond is also biocompatible towards large biomolecules, such as DNA.…”