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Lookup NU author(s): Yimin Chao,
Professor Lidija Siller
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Spectroscopic Photoemission Low Energy Electron Microscopy (SPELEEM) has been used to investigate HiPCO single-wall carbon nanotubes (SWNTs) supported on a polycrystalline gold substrate. Data obtained at a spatial resolution of ∼50nm enabled both imaging and spectroscopic investigation of the samples. Imaging with C1s core level electrons (XPEEM mode) and secondary electrons (SEEM mode) reveals tangled SWNT bundles, in agreement with Atomic Force Microscopy (AFM) studies on the same samples. The contrast in SEEM indicates that the work function of the nanotube bundles is larger than that of the air-exposed gold substrate, as expected. Spatially resolved C1s spectra obtained from the nanotube bundles are found to be uniform along the length of a given unique bundle. However, considerable heterogeneity is found between bundles, reflected in differences in core level binding energy and linewidth. These differences are correlated with the spectral intensity from the bundles and hence bundle diameter - in thin bundles a greater proportion of the nanotubes interact with the substrate, perturbing core level emission. Small regions with strongly different lineshapes can be observed in some nanotube bundles, which are assigned to the presence of defects and contamination. Such inter-bundle and intra-bundle variations are averaged out in conventional spectroscopy and show the power of the SPELEEM technique to investigate physico-chemical properties of inhomogeneous nanostructured materials. © 2004 The Electrochemical Society, Inc.
Author(s): Chakraborty AK, Woolley RAJ, Chao Y, Siller L, Hunt MRC
Publication type: Conference Proceedings (inc. Abstract)
Publication status: Published
Conference Name: 205th Meeting of The Electrochemical Society
Year of Conference: 2004
Publisher: Electrochemical Society, Inc.