Preparation and functional characterizations of Ta2O5 deposits organized at the nanoscale

The present communication deals with the coating of bundles of single wall carbon nanotube (SWCNTs) by nanocrystalline tantalum pentoxide (Ta2O5) deposits. Arrays of SWCNTs bundles are produced on Si and AlN plates by means of a Hot Filament CVD apparatus, using as reactants carbon nanopowders and in-situ produced atomic hydrogen. A subsequent process, carried out in an O2-rich atmosphere, enables to cover the bundles by a uniform deposit of Ta2O5 nanograins. The coating process does not modify the organization of the pristine nanotube deposits. A series of SWCNT/Ta2O5 samples, characterized from both the morphological and structural point of view, have been tested as cathodes in Field Emission experiments (F.E.). The F.E. experiments proved that these hybrid SWCNT/dielectric systems are good field emitters and that their properties make them suitable for the realization of cold cathodes.