Characterization of amorphous carbon-hydrogen films by solid-state nuclear magnetic resonance

Abstract

The structure and properties of thin amorphous carbon films are critically dependent upon the preparation conditions. Hydrogenated amorphous carbon films, prepared by both ion beam sputtering and glow discharge techniques, have been investigated by solid-state 13C magic angle spinning nuclear magnetic resonance measurements of the sp2 and sp3 bonding sites. Film hardness and density correlate with the incorporated hydrogen, whereas the optical band gap is controlled by the fraction of tetrahedral (sp3) versus graphitic (sp2) bonding. It is shown that structural trade-offs prevent the formation of so-called amorphous diamond, i.e., a material with simultaneous extreme hardness and wide optical band gap.

Amorphous, Hydrogenated Carbon Films and Related Materials: Plasma Deposition and Film Properties

“…It has been shown that a-C:H contains both Sp2 and sp3-hybridized carbon atoms, the latter being the dominant fraction (see table 2). These data have been confirmed later by nuclear magnetic resonance (NMR) [33,34]. NMR also revealed [34] that tetrahedral sp3_ carbon atoms are bonded to at least one hydrogen atom, i.e.…”

Structural analysis of amorphous carbon films by spectroscopic ellipsometry, RBS/ERDA, and NEXAFS

“…%, 12,[32][33][34] while it seems to be a discontinuous distribution below 20%. [35][36][37] The existence of the gaps should be important evidence and root cause that is why the amorphous carbon films can be classified and also corresponds to the results of the analysis in Fig. 3(a).…”

Solid state magnetic resonance investigation of the thermally-induced structural evolution of silicon oxide-doped hydrogenated amorphous carbon

“…This lack of knowledge inhibits developing a fundamental understanding of the mechanisms by which the excellent thermal stability and tribological performance of a-C:H:Si:O are achieved. To gain insights into the structure and composition of DLCs, some of the most powerful tools in the material characterization arsenal have been used, including Raman spectroscopy [9,[16][17][18][19], X-ray photoelectron spectroscopy (XPS) [13,20,21], near edge X-ray absorption fine structure (NEXAFS) spectroscopy [22][23][24], electron energy loss spectroscopy (EELS) [25], Fourier-transform infrared spectroscopy (FT-IR) [26], X-ray reflectivity (XRR) [25], forward recoil elastic scattering (FRES) [27], nuclear magnetic resonance (NMR) spectroscopy [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41], and electron paramagnetic resonance (EPR) spectroscopy [42][43][44][45][46].…”