Spectroscopic characterization of β-FeSi2 single crystals and homoepitaxial β-FeSi2 films by XPS and XAS

Chemical state analysis by a combination of X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) using synchrotron radiation is performed for beta-FeSi2 single crystals and homoepitaxial beta-FeSi2 films. The Si 2p XPS and Fe L-edge XAS spectra imply that the annealing at 1173 K to remove native oxide layers on the crystal induces the formation of FeSi in the surface. The formation of FeSi is also confirmed by Si K-edge XAS analysis. For the homoepitaxial beta-FeSi2 films grown on the crystals, the Si K-edge XAS spectra indicate that structurally homogeneous beta-FeSi2 films can be grown on the beta-FeSi2 single crystals when the substrate temperatures of 973 and 1073 K are applied for molecular beam epitaxy (MBE). Consequently, it is indicated that the combination of XPS and XAS using synchrotron radiation is a useful tool to clarify chemical states of beta-FeSi2 single crystals and homoepitaxial beta-FeSi2 films, which is important to reveal optimized growth conditions of homoepitaxial films. (C) 2010 Elsevier B.V. All rights reserved.