Soft X-ray emission and absorption spectra in the C K region of sputtered amorphous carbon films

Abstract Soft X-ray emission and absorption spectra in the C K region of amorphous carbon films systematically deposited by RF, ion-beam, and ECR sputtering under various deposition conditions were measured using highly brilliant synchrotron radiation. A broad main peak and a high-energy shoulder were observed in the emission spectra, and a fine structure consisting of at least five peaks was observed in the absorption spectra. By analogy to the occupied/unoccupied C2p-DOS obtained by DV-Xα molecular orbital calculations of simple cluster models composed of sp 2 and sp 3 carbon atoms, we approximately explained the spectral features in the measured X-ray emission spectra by σ and π bonds and estimated the fine structures in the absorption spectra by the hybridized unoccupied molecular orbitals formed by the local-structures composed of sp 2 and sp 3 carbon atoms.