Photoemission study of amorphous and crystalline GeTe and (Ge,Mn)Te semiconductors

• Monocrystalline and amorphous layers of GeTe and (Ge,Mn)Te were grown on BaF2 (111) monocrystalline substrates by molecular beam epitaxy technique.
• The electronic structure of amorphous and monocrystalline GeTe and (Ge,Mn)Te layers was studied by resonant photoemission spectrosocopy (RPES) technique.
• Configuration interaction analysis reveals stronger p–d hybridization of electronic states in monocrystalline (Ge,Mn)Te layers.

Resonant photoemission spectroscopy was applied to compare the valence band structure of Ge0.9Mn0.1Te and GeTe semiconductor layers deposited on BaF2 substrate in monocrystalline and amorphous forms. In (Ge,Mn)Te the contribution of Mn 3d5 electronic orbitals to density of states was found in three binding energy regions: below the top of the valence band (Eb<4.2 eV), at the binding energy range 4.2–4.4 eV, and in many-body satellite at 9–13 eV. The comparative analysis of the photoemission spectra based on configuration interaction model showed that p–d hybridization effects, important for magnetic and optical properties of (Ge,Mn)Te, are stronger in monocrystalline than in amorphous (Ge,Mn)Te layers.