Synthesis and characterization of single-wall carbon nanotube–amorphous diamond thin-film composites

Abstract

Thin-film single-wall carbon nanotube (SWNT) composites synthesized by pulsed laser deposition (PLD) are reported. Ultrahard, transparent, pure-carbon, electrically insulating, amorphous diamond thin films were deposited by PLD as scratch-resistant, encapsulating matrices for disperse, electrically conductive mats of SWNT bundles. In situ resistance measurements of the mats during PLD, as well as ex situ Raman spectroscopy, current–voltage measurements, spectroscopic ellipsometry, and field-emission scanning electron microscopy, are used to understand the interaction between the SWNT and the highly energetic (∼100 eV) carbon species responsible for the formation of the amorphous diamond thin film. The results indicate that a large fraction of SWNT within the bundles survive the energetic bombardment from the PLD plume, preserving the metallic behavior of the interconnected nanotube mat, although with higher resistance. Amorphous diamond film thicknesses of only 50 nm protect the SWNT against wear, providing scratch hardness up to 25 GPa in an optically transmissive, all-carbon thin-film composite.