IDENTIFICATION OF DIFFERENT FORMS OF CARBON BY EXTENDED ENERGY-LOSS FINE-STRUCTURE

Using extended energy loss fine structure spectroscopy (EXELFS), we ob tained the local structure around the carbon atoms in amorphous carbon , highly oriented pyrolytic graphite and a polycrystalline diamond thi n film grown by the HF-CVD technique. The experiments were performed i n a scanning Auger microprobe in the reflection mode and in a high res olution transmission electron microscope with a PEELS attachment. The values obtained for the local structure applying these techniques, sho w an error around 12% for EXELFS in the reflection mode and 0.3% for t he transmission mode, with respect to their reported crystallographic values. In order not to alter the raw experimental data obtained for t he different forms of carbon under the same experimental conditions, t he introduction of empirical phase shifts was not applied here. This w as done in order to avoid the introduction of empirical phase shifts w hich are normally used to fit the data to know structural parameters. One of the main objectives of this work is to test the reproducibility of the data when taken in the reflection and in the transmission mode s.