A photo emission study of c-axis-oriented thin films of α-(BEDT-TTF)2I3

Abstract

Highly c-axis-oriented thin films of α-(BEDT-TTF)2I3 have been prepared by physical vapour deposition. Structural and morphological characterization are performed by X-ray diffraction and scanning electron microscopy. In situ photoemission experiments on the films reveal five distinct features in the valence-band regime; the two structures with the lowest binding energies are assigned to molecular orbitals present in the TTF backbone. None of the valence-band structures shows dispersion along the Γ-Z(k2) direction. The spectral intensity is zero at, and to within 0.5 eV of the Fermi level. Core-level spectroscopy on the I 4d level indicates that all iodine is present as I3-ions and that the surface consists of BEDT-TTF molecules.