The Role of Oxygen at the Interface between Titanium and Carbon Nanotubes

Alexandre Felten (1) , Irene Suarez-Martinez (2) , Xiaoxing Ke (3) , Gustaaf van Tendeloo (3) , Jacques Ghijsen (1) , Jean Jacques Pireaux (1) , Wolfgang Drube (4) , Carla Bittencourt (5) , Christopher Ewels (2)

1 PMR - Centre de Recherche en Physique de la Matière et du Rayonnement [Namur]
2 IMN - Institut des Matériaux Jean Rouxel
3 EMAT - Electron Microscopy for Materials Science
4 DESY - Deutsches Elektronen-Synchrotron [Zeuthen]
5 LCIA - LCIA

We study the interface between carbon nanotubes (CNTs) and surface-deposited titanium using electron microscopy and photoemission spectroscopy, supported by density functional calculations. Charge transfer from the Ti atoms to the nanotube and carbide formation is observed at the interface which indicates strong interaction. Nevertheless, the presence of oxygen between the Ti and the CNTs significantly weakens the Ti–CNT interaction. Ti atoms at the surface will preferentially bond to oxygenated sites. Potential sources of oxygen impurities are examined, namely oxygen from any residual atmosphere and pre-existing oxygen impurities on the nanotube surface, which we enhance through oxygen plasma surface pretreatment. Variation in literature data concerning Ohmic contacts between Ti and carbon nanotubes is explained via sample pre-treatment and differing vacuum levels, and we suggest improved treatment routes for reliable Schottky barrier-free Ti–nanotube contact formation.

Mots clés: nanotube; graphene; interface; DFT; XPS; titanium; oxygen

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Alexandre Felten, Irene Suarez-Martinez, Xiaoxing Ke, Gustaaf van Tendeloo, Jacques Ghijsen, et al.. The Role of Oxygen at the Interface between Titanium and Carbon Nanotubes. ChemPhysChem, 2009, 10, pp.1799. ⟨10.1002/cphc.200900193⟩. ⟨hal-00423308⟩