Photoemission study on the valence band of a β-FeSi2 thin film using synchrotron radiation

Abstract

Resonant and constant-initial state photoemission spectroscopies using synchrotron radiation were applied to investigate the valence-band electronic structure of a semi-conducting β-type iron-disilicide (β-FeSi₂) thin film. The results clearly indicated that the component elements, iron (Fe) and silicon (Si), contribute differently to the valence band features; the Fe 3d orbitals mainly concentrate in the top region of the valence band while the Si 3s and 3p orbitals spread over the wide region of the valence band. The β-FeSi₂ thin film showed a typical p-type semi-conducting nature with a work function of 4.78 eV. The β-FeSi₂ film showed the Fe M₁VV Auger lines around the kinetic energy of 88 eV. It would be expected from these observations that there exist strong interactions between iron and silicon atoms in the β-FeSi₂ film resulting in orbital mixing and band formation.