Structural defects in glassy As2Se3 are classified and labeled according to the constituent like-atom bonds and malcoordinated atoms. A selection rule is formulated to reduce the number of allowed Fermi-level pinning reactions. An elementary Bethe-lattice model is introduced as a starting point for a discussion of the electronic structure of simple defects. The defect states are found to be very different from those in Se; deep gap states arise in As2Se3 because of unique bond orbitals, whereas they occur in Se due to unique interactions between orbitals. Malcoordinated Se atoms are expected to give rise to hydrogenic levels in As2Se3, in contrast to Se. Surprisingly, the undercoordinated pnictide defects are positively charged in this model. Finally, defect creation energies and densities at Tg are discussed.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics