title: 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.
authors.affiliation: Department of Nano Science, Cheongju University, Cheongju 360-764, Korea.
authors.forename: Byeongchul
authors.initials: B
authors.lastname: Ha
authors.forename: Jeunghee
authors.initials: J
authors.lastname: Park
authors.forename: Shin Young
authors.initials: SY
authors.lastname: Kim
authors.forename: Cheol Jin
authors.initials: CJ
authors.lastname: Lee