AVS 49th International Symposium
    Nanotubes: Science and Applications Topical Conference Tuesday Sessions
       Session NT-TuP

Paper NT-TuP2
STM Investigation of Oxygen Adsorption on Carbon Nanotubes

Tuesday, November 5, 2002, 5:30 pm, Room Exhibit Hall B2

Session: Poster Session
Presenter: S. Santucci, INFM and University of L'Aquila, Italy
Authors: S. Santucci, INFM and University of L'Aquila, Italy
L. Lozzi, INFM and University of L'Aquila, Italy
M. Simeoni, INFM and University of L'Aquila, Italy
M. Passacantando, INFM and University of L'Aquila, Italy
L. Valentini, University of Perugia, Italy
I. Armentani, University of Perugia, Italy
J.M. Kenny, University of Perugia, Italy
Correspondent: Click to Email
Carbon nanotubes, thanks to their electronic and structural properties, are studied for many important applications. One recently interesting application is the gas sensing. In fact it has been shown that the electrical conductance of single-walled carbon nanotubes (SWNTs) can be drammaticaly changed upon exposure to gaseous molecules such as NO2, NH3@footnote 1@or O2.@footnote 2@ These molecules can be adsorbed both at the nanotube surface or can be accepted inside the nanotube.@footnote 3@ In this work we will present STM/STS data acquired onto multi-walled carbon nanotubes (MWNTs) during the exposure to O2 molecules. The MWNT films have been deposited by plasma enhanced chemical vapor deposition (PECVD) using Ni as catalyst particles on silicon. These samples have been exposed to O2, keeping the sample at different temperatures, in order to simulate the gas sensing processes (adsorption/desorption). The adsorption of O2 determines the variation of STS curves, showing the presence of new states, both filled and empty ones, which can be assigned to the interaction between molecules and MWNTs. These states also depend on the sample temperature, in particular the empty ones. The desorption process has been also followed, showing the missing of the oxygen-MWNT states when oxygen is removed from the STM chamber. @FootnoteText@ @footnote 1@ J.Kong, N.R. Franklin, C. Zhou, M.G. Chapline, S. Peng, K. Cho, H. Dai, Science 287 (2000) 622.@footnote 2@ P.G. Collins, K. Bradley, M. Ishigami, A. Zettl, Science 287 (2000) 1801.@footnote 3@ A. Fujiwara, K. Ishii, H. suematsu, H. Kataura, Y. Maniwa, S. Sizuki, Y. Achiba, Chem. Phys. Lett. 336 (2001) 205. .