title: Fermi level engineering of single-walled carbon nanotubes by AuCl3 doping.
abstract: We investigated the modulation of optical properties of single-walled carbon nanotubes (SWCNTs) by AuCl 3 doping. The van Hove singularity transitions (E 11 (S), E 22 (S), E 11 (M)) in absorption spectroscopy disappeared gradually with an increasing doping concentration and a new peak appeared at a high doping concentration. The work function was downshifted up to 0.42 eV by a strong charge transfer from the SWCNTs to AuCl 3 by a high level of p-doping. We propose that this large work function shift forces the Fermi level of the SWCNTs to be located deep in the valence band, i.e., highly degenerate, creating empty van Hove singularity states, and hence the work function shift invokes a new asymmetric transition in the absorption spectroscopy from a deeper level to newly generated empty states.
authors: BK21 Physics Division, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
authors: Ki Kang
authors: KK
authors: Kim
authors: Jung Jun
authors: JJ
authors: Bae
authors: Hyeon Ki
authors: HK
authors: Park
authors: Soo Min
authors: SM
authors: Kim
authors: Hong-Zhang
authors: HZ
authors: Geng
authors: Kyung Ah
authors: KA
authors: Park
authors: Hyeon-Jin
authors: HJ
authors: Shin
authors: Seon-Mi
authors: SM
authors: Yoon
authors: Anass
authors: A
authors: Benayad
authors: Jae-Young
authors: JY
authors: Choi
authors: Young Hee
authors: YH
authors: Lee