Extended Fine Structures in Diamond and Related Materials

Abstract
Many work deal with diamond and related materials (c-BN and the hypothetical C₃N₄ compound) thin films synthesis. It is necessary to characterize the structure of such films at the atomic scale. The X ray absorption (XAS) and electron energy loss (EELS) spectroscopies are well adapted for such purposes, but they raise a difficult problem for theoretical codes due to large chemical bonding effects at low energies. Taking diamond as an example, we will show that FEFF6 is adequate for EXAFS calculations. Furthermore, FEFF6 can be used as a starting point of a new XANES code that includes an exact full multiple scattering calculation. The usefulness of this new code will be illustrated by comparing theoretical XANES (diamond) and ELNES (c-BN) spectra. Results related to the theoretically predicted C₃N₄ compound will be also briefly discussed.