Evidence of Carboxyl Modification of Hydrogen-Free Diamond-Like Carbon Films Assisted by Radio Frequency Plasma in Vacuum
Figure 2
X-ray photoelectron spectroscopy (XPS) C1s spectra, for the original DLC film (dots, S1), the surface hydrogenated DLC (square, S2), and the AA-modified DLC film with RF power of 20 W (triangle, S5) (a), which are normalized to a total intensity of 50000; that for AA-modified without RF plasma assistance (S3) for 60 min (b); that for AA-modified with RF power of 20 W (S5) for 60 min (c). The fitted curves are deconvolved into sp2 carbon at 284.7 eV, sp3 carbon at 285.5 eV, C–O at 286.4 eV, C=O at 287.3 eV, and –COOH at 288.5 eV.
