Surface Modification of Nanocrystalline Diamond/Amorphous Carbon Composite Films

The surfaces of nanocrystalline diamond/amorphous carbon (NCD/a-C) nanocomposite films deposited from a 17% CH4/N2 mixture have been subjected to a variety of plasma and chemical treatments, namely H2 and O2 microwave plasmas, a CHF3 13.56 MHz plasma, and a chemical treatment with aqua regia (HCl:HNO3 3:1). The resulting surfaces have been studied with respect to their chemical nature by X-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (TOF-SIMS), concerning their morphology with atomic force microscopy, and by contact angle measurements to study their hydrophobicity and their stability. As-grown surfaces are hydrogen terminated, but the number of C-H bonds can slightly be increased by a H2 microwave plasma, while treatment with aqua regia considerably lowers the number of C-H bonds at the surface. O2 and CHF3 plasmas, on the other hand, lead to a replacement of the terminating C-H bonds by C-O or C-OH and C-Fx groups, respectively. Finally, by contact angle measurements over a period of 150 days it could be shown that the H-terminated surface is very stable whereas the contact angle of the O-treated surface changed considerably with time, probably due to the adsorption of contaminants.

POPOV Cyril;  KULISCH Wilhelm;  BLIZNAKOV S.;  CECCONE Giacomo;  GILLILAND Douglas;  SIRGHI Lucel;  ROSSI Francois; 

2008-12-17

ELSEVIER SCIENCE SA

JRC48885

0925-9635,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC48885,   

10.1016/j.diamond.2008.01.078,