Photoemission (XPS and UPS) measurements were performed for elemental Se and Bi and, crystalline and amorphous Bi2Se3 films to terminate the long-standing controversy about the charge transfer in Bi-doped chalcogenide glasses. It was elucidated that the Bi atoms in amorphous Bi2Se3 are positively charged owing to an electronic charge transfer from the Bi atoms to the Se atoms. A comparison of the chemical shift of the core levels and the valence band between amorphous and crystalline Bi2Se3 indicates that the bonding is more covalent in amorphous phase than in crystalline phase, suggesting that although the Bi atoms in crystalline Bi2Se3 are six-fold coordinated by Se atoms, the Bi atoms in the amorphous phase are three-fold coordinated like the As and Sb atoms in amorphous chalcogenides.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Materials Chemistry