Photoemission spectroscopy of single-walled carbon nanotube bundles

The electronic structures and the work functions of pristine and Cs-intercalated single-walled carbon nanotube bundles were investigated by C 1s and valence band photoemission spectroscopy. The C 1s spectrum of the pristine material showed a Doniach-Sunjic type asymmetry, indicating the existence of metallic tubes. The work function of the pristine bundles was found to be 4.8 eV, which is about 0.2 eV larger than that of graphite. A drastic decrease of the work function to about 2.0 eV was observed in the Cs-intercalated sample. The Cs intercalation also caused a nearly two-order increase in the spectral intensity at the Fermi level. (C) 2001 Elsevier Science B.V. All rights reserved.