Electron trapping in substoichiometric germanium oxide

Abstract

Model structures of substoichiometric germanium oxide generated by ab initio molecular dynamics reveal a rich variety of bonding configurations, including threefold coordinated Ge and O atoms which correspond to valence alternation pairs. A sizable fraction of twofold Ge atoms carrying unoccupied dangling bonds is also found. The present structures are prone to electron capture. The electrons are trapped in additionally formed Ge–Ge bonds. The associated defect levels fall within the Ge band gap and could explain the poor performance of n-type Ge devices.