The spectroscopic investigation of the optical and electronic properties of SWCNT

Abstract

The spectroscopic investigation of bulk samples of SWCNT is reviewed with examples taken from electron energy-loss spectroscopy in transmission, UV-vis and photoemission spectroscopy. It is shown that, given the insight obtained from EELS studies, UV-vis spectroscopy is a powerful express tool for the characterization of the NT yield and diameter distribution in bulk SWCNT samples. In addition, using photoemission spectroscopy, apart from showing the use of annealing in UHV to remove many of the contaminants commonly found in purified SWCNT material and determining the work function of pristine SWCNT to be 4.65±0.1 eV, we illustrate the similarity of the occupied electronic structure of SWCNT with that of graphite. Open questions, however, remain, such as the appropriate model for the changes of the electronic structure upon intercalation and the reasons for the absence of the singularities in the occupied density of states in the photoemission spectra.