Koidl, P.P.KoidlRamsteiner, M.M.RamsteinerWagner, J.J.WagnerWild, C.C.Wild2022-03-022022-03-021989https://publica.fraunhofer.de/handle/publica/17766810.1103/PhysRevB.40.18172-s2.0-0000334054Resonant Raman scattering has been used to study amorphous carbon and polycrystalline diamond films. The incident photon energies were varied over the range 2.2-4.8 eV. In hydrogenated amorphous carbon films containing both sp high 3 and sp high 2 bonded carbon, a high-frequency shift is interpreted in terms of scattering from pi-bonded carbon clusters which is resonantly enhanced for photon energies approaching the pi-pi resonance of sp high 2 bonded carbon. In polycrystalline diamond films excitation with photon energies equal or bigger than 3.0 eV enhances the Raman signal from sp high 3 bonded diamond phase relative to the scattering by sp high 2 bonded carbon and with respect to the underlying broadband luminescence. The Raman band arising from scattering by sp high 2 bonded carbon shows a high-frequency shift with increasing photon energy for energies equal or bigger than 3.0 eV. Possible models for the structure of this sp high 2 bonded carbon phase are discussed on the basis of the present Raman data.enamorpher Kohlenstoffamorphous carbonpolycrystalline diamondpolykristalliner Diamantresonant Raman scatteringresonante Ramanstreuung621667530journal article