Secondary electron-, Auger electron- and reflected electron-spectroscopy study on sp2-hybridization carbon materials: HOPG, carbon glass and carbon fiber

Auger electron spectroscopy (AES) has been a widely used technique for elemental composition determination. However, it is difficult to be used for characterization of materials with the identical or similar elemental compositions, such as sp(2)-hybridization materials. In addition, reflection electron energy loss spectroscopy (REELS) also shows a high degree of spectrum similarity for allotropic materials. We found that, comparing with the AES signals, the secondary electron spectroscopy (SES) signals generated as a byproduct in the measured full direct AES spectrum hold the potential for the identification of allotropic materials. This is because the SES signals are material dependent and are strongly influenced by the density of unoccupied states of the materials. Here, we present a study of the SES spectra for three sp(2)-hybridization carbon materials, i.e. the highly oriented pyrolytic graphite, carbon fiber and carbon glass, with typically different long-range orders. The results indicate that SES is applicable to the structural characterization of allotropic materials.