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

Soft X-ray emission and absorption spectra in the C K region of amorphous c arbon films systematically deposited by RF, ion-beam, and ECR sputtering un der various deposition conditions were measured using highly brilliant sync hrotron radiation. A broad main peak and a high-energy shoulder were observ ed in the emission spectra, and a fine structure consisting of at least fiv e peaks was observed in the absorption spectra. By analogy to the occupied/ unoccupied C2p-DOS obtained by DV-X alpha molecular orbital calculations of simple cluster models composed of sp(2) and sp(3) carbon atoms, we approxi mately explained the spectral features in the measured X-ray emission spect ra by sigma and pi bonds and estimated the fine structures in the absorptio n spectra by the hybridized unoccupied molecular orbitals formed by the loc al-structures composed of sp(2) and sp(3) carbon atoms. (C) 2001 Elsevier S cience Ltd. All rights reserved.