Presentation Information
[2P29]Characterization of electronic states in single-walled carbon nanotubes by near ambient pressure XPS
*Takahiro Nishio1, Masafumi Horio2, Yoshimasa Hijikata1, Hiroshi Okada3, Yutaka Matsuo3, Iwao Matsuda2, Taisuke Ono1 (1. Advanced Research and Innovation Center, DENSO CORPORATION, 2. Institute for Solid State Physics, The University of Tokyo, 3. Department of Chemical Systems Engineering, Nagoya University)
Single-walled carbon nanotubes(SWCNTs) are promising materials for flexible, lightweight electronic devices. However, previous studies have reported that under ambient environment the system tends to show p-type character due to a hole doping effect by oxygen or water adsorbed onto the surface, making it difficult to obtain the desired properties. Then, it is required to evaluate the amount of the adsorbed oxygen and their electronic state of the SWCNTs under various environmental conditions quantitatively. In this study, we employed ambient pressure X-ray photoemission spectroscopy (AP-XPS) at NanoTerasu BL08U. The XPS spectra obtained under two conditions: after heating in vacuum at 573 K and cooling to below 373 K to establish the initial state, and during subsequently heating the sample in an oxygen atmosphere. As a result of fitting, the oxygen-to-carbon ratio was increased from 0.037 to 0.053 mol/mol. Furthermore, a low-energy shift in the C1s peak was detected, which is considered to result from the Fermi energy shifting towards the valence band side due to p-type doping.