| AVS 60th International Symposium and Exhibition | |
| Surface Science | Tuesday Sessions |
| Session SS-TuP |
| Session: | Surface Science Poster Session |
| Presenter: | R.S. Shibuya, University of Tsukuba, Japan |
| Authors: | R.S. Shibuya, University of Tsukuba, Japan M. Sakurai, University of Tsukuba, Japan Y. Saito, University of Tsukuba, Japan K. Kawarai, University of Tsukuba, Japan T. Kondo, University of Tsukuba and PREST JST, Japan J. Nakamura, University of Tsukuba, Japan |
| Correspondent: | Click to Email |
The graphite surface consists of the p conjugated system which originates from the resonance of the 2pZ electron orbital of the carbon atoms and it is well known as an inert surface. However, because of the perturbation of π conjugated system, the non-bonding π electronic states of the graphite-related materials such as graphene sheets and graphite are known to appear as the localized states at the carbon atoms around the zigzag edge,1,2 metal cluster,3 defects,4 and dopants. We have reported that localized non-bonding electronic states near the Fermi level in the unoccupied region at carbon atoms around point defects of graphite by scanning tunneling microscopy/ spectroscopy (STM/STS). This localized state propagates with threefold symmetry perpendicular to the zigzag edges at the point defect. Considering that the carbon atoms with the localized state may act as an acid site, we have examined the ammonia adsorption properties on graphite surface with point defects. In this work, we have prepared the defect induced HOPG surface (Ar+/HOPG) by Ar ion bombardment (ion energy is 140 eV and coverage of defect is 1%). We investigated the ammonia adsorption properties on Ar+/HOPG by Temperature programmed desorption (TPD). Helium atom scattering (HAS), XPS, and STM/STS. From TPD and HAS, we found that ammonia weekly chemisorbed near the defects at 110 K.The detail of adsorption features will be discussed in the presentation with our STM /STS and XPS results .
1. M. Fujita, et al., J. Phys. Soc. Jpn., 65 (1996) 1920.
2. Y. Niimi, et al., Appl. Surf. Sci., 241 (2005) 43; Y. Kobayashi, et al., Phys. Rev. B 71 (2005) 193406 .
3. T. Kondo, Y. Iwasaki, Y. Honma, Y. Takagi, S. Okada and J. Nakamura, Phys. Rev. B 80 (2009) 233408.
4. T. Kondo, Y. Honma, T. Machida, J. Oh, J. Nakamura, Phys. Rev. B 82 (2010) 153414