Structural properties of the diamond nucleation layer on iridium analyzed by laterally resolved X-ray absorption spectroscopy

The complex structure of the diamond nucleation layer on iridium has been studied by X-ray absorption near edge structure (XANES) in combination with X-ray photoemission electron microscopy (X-PEEM). In contrast to all other substrate materials, on iridium the diamond nuclei formed by the bias enhanced nucleation (BEN) procedure gather in islands (domains) with micron-size lateral dimensions. Laterally resolved XANES spectra of the carbon-K absorption edge clearly show the difference in carbon bonding structure Outside and inside the domain area. A positive feedback mechanism for the nucleation and lateral crystal growth, are two alternative concepts which can explain the domain formation.