Elastic constants of tetrahedral amorphous carbon films by surface Brillouin scattering
نویسندگان
چکیده
The elastic constants of tetrahedral amorphous carbon ~ta-C! and hydrogenated tetrahedral amorphous carbon ~ta-C:H! thin films were determined nondestructively by surface Brillouin scattering. Besides the usual Rayleigh surface mode, we also observe a new pseudosurface acoustic mode of longitudinal polarization, which is a modified version of the longitudinal guided mode usually found in slow-on-fast supported films. The Young’s modulus E of a ta-C with 88% sp is 757 GPa, and the shear modulus G is 337 GPa. The moduli of ta-C:H with 70% sp and 30 at. % H are lower, E5300 GPa and G5115 GPa. © 1999 American Institute of Physics. @S0003-6951~99!02538-3#
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