Defect states at III-V semiconductor oxide interfaces

Models of insulating interfaces between (100)GaAs and HfO2, Gd2O3, and Al2O3 are constructed and used to host various interfacial defects to see which give rise to gap states. The antibonding state of As–As dimers is found to lie in the upper band gap and is identified as a possible major source of the interface gap states which cause Fermi level pinning in GaAs-oxide interfaces and field effect transistors.