Investigation of Field Emission and Photoemission Properties of High-Purity Single-Walled Carbon Nanotubes Synthesized by Hydrogen Arc Discharge

Abstract

Single-walled carbon nanotubes (SWCNTs) were directly synthesized by a hydrogen arc-discharge method by using only Fe catalyst. The synthesized carbon materials indicated high-purity SWCNTs without amorphous carbon materials from SEM observation. The SWCNTs had diameters of 1.5-2.0 nm from TEM and Raman observation. After a simple purification, TGA indicated that SWCNTs had a purity of ca. 90.1 wt %. Field emission from the SWCNT emitters which were fabricated by using a spray method was measured by a diode structure. The vertically aligned SWCNT emitters showed the low turn-on voltage of 0.86 V/microm and a high emission-current density of 3 mA/cm2 at an applied field of about 3 V/microm. From a Fowler-Nordheim plot, the vertically aligned SWCNT revealed a high field enhancement factor of 2.35 x 10(4). The photoemission measurements, excited by a photon energy of 360 eV, showed significantly delocalized graphite-pi states at the purified SWCNTs. Here, we investigated that the field-emission properties of SWCNTs would be attributed to the high electronic density of states near Fermi energy, including the delocalized graphite-pi states.

Effect of heat-pretreatment of the graphite rod on the quality of SWCNTs by arc discharge

“…The lower E to and E th are superior to the SWCNT that were grown by arc discharge without heat-treatment having even been reported. Among these, Bonard et al have obtained excellent field emitters, yielding E to = 1.5-4.5 V/mm and E th = 4-7 V/mm [14][15][16][17].…”

Elution behavior of shortened multiwalled carbon nanotubes in size exclusion chromatography

“…A pure MWCNT sample was received as a kind gift from Korea University. This was synthesized by chemical vapor deposition (CVD) in acetylene gas using Fe‐Mo/Al 2 O 3 as the catalyst . As characterized in our previous study, the average diameter of the MWCNTs was 10–30 nm, and the sample contained less than 5% mixed impurities of catalyst and amorphous carbon species .…”

Carbon Nanotube Electron Sources: From Electron Beams to Energy Conversion and Optophononics

“…This is in the ultraviolet (UV) or X-ray ranges. Photoemission from carbon nanotubes using high-energy photons has been studied by many, primarily in the form of spectroscopy for the investigation of the electronic structure of nanotubes under various conditions [151][152][153][154][155][156] and photoemission microscopy [157,158]. The photon energies in these cases are high enough to probe deep electronic levels.…”