| AVS 54th International Symposium | |
| Nanometer-scale Science and Technology | Thursday Sessions |
| Session NS-ThA |
| Session: | Nanoscale Sensors |
| Presenter: | J.J. Pireaux, Namur University, Belgium |
| Authors: | A. Felten, Namur University, Belgium J. Ghijsen, Namur University, Belgium W. Drube, HASYLAB, Germany R.L. Johnson, University of Hamburg, Germany D. Liand, University of Antwerp, Belgium G. Van Tendeloo, University of Antwerp, Belgium M. Hecq, Mons University, Belgium C. Bittencourt, Materianova, Belgium J.J. Pireaux, Namur University, Belgium |
| Correspondent: | Click to Email |
The study of the electronic interaction between metal atoms and carbon nanotubes is essential in order to improve performances of devices such as nano-transistors or gas sensors, for example to achieve low-resistance electrical contacts. Palladium and titanium decorated multiwall carbon nanotubes appear to be good candidates for such applications. In this work, both high resolution transmission electron microscopy (HRTEM) and photoemission spectroscopy have been used. Different amounts of Ti and Pd were evaporated onto both pristine and oxygen plasma functionalized carbon nanotubes. HRTEM images show the evolution of the morphology of the metal overlayer onto the nanotube surface. Evaporation of Ti on pristine nanotubes leads to a continuous coverage even for a very low amount of evaporated metal. In contrast, Pd deposition is characterized by the formation of small clusters. Oxygen plasma treatment is seen to improve the Pd cluster dispersion and size distribution. Analysis of the core and valence bands in photoemission spectroscopy reveals also strong differences between the two metals. The appearance of a new peak at lower binding energy on the C 1s level for Ti decorated nanotube is associated to the formation of Ti-C bonds (high coverage), with evidence of a charge transfer from titanium atoms to the carbon nanotube at low coverage For Pd on the contrary, the absence of new features in both Pd 3d and C 1s spectra are suggesting the absence of a mixed Pd-C phase.
This work is financially supported by the Nano2Hybrids (EC-STREP-033311) and PAI 6/1 projects, and by DESY and the EC under contract RII3-CT 2004-506008 (IASFS).