Fermi level engineering of single-walled carbon nanotubes by AuCl3 doping.
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.
Kim
Ki Kang
KK
BK21 Physics Division, Center for Nanotubes and Nanostructured Composites, Sungkyunkwan Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
Bae
Jung Jun
JJ
Park
Hyeon Ki
HK
Kim
Soo Min
SM
Geng
Hong-Zhang
HZ
Park
Kyung Ah
KA
Shin
Hyeon-Jin
HJ
Yoon
Seon-Mi
SM
Benayad
Anass
A
Choi
Jae-Young
JY
Lee
Young Hee
YH