Analysis of the electronic structure of hydrogenated amorphous carbon via Auger spectroscopy

The X-ray excited Auger electron spectroscopy XAES.has been used to investigate the pp electronic structure of hydrogenated amorphous carbon a-C:H.films, at different hydrogen content. The X-ray Photoelectron Spectra XPS.of the C1s core level with the associated photoelectron energy loss spectrum PELS.have been recorded simultaneously to the XAES data. It has been proved that the double-differentiated ppUpp Auger self-fold contribution to the CKVV Auger spectrum is very sensitive to the hydrogen content andror sample preparation conditions, providing a reliable fingerprint of the material. The extent of the electronic gap and the fraction of sp2 sites of the a-C:H films have been estimated. The features of the Auger ppUpp self-fold structure can be associated to those appearing in the electronic density of states evaluated using Molecular Dynamics simulations. q1999 Elsevier Science B.V. All rights reserved