Electronic Structure and Band Gap Engineering of ZnO-based Semiconductor Alloy Films

摘要

We conduct first-principles total-energy density functional calculations to study the atomic structures, band structures, and electronic structures of Zn_(1-x)M_xO (M = Be, Mg, Cd, Ag, Cu) semiconductor alloys. The Heyd-Scuseria-Ernzerhof (HSE) hybrid functional has been performed to yield lattice constants and bandgaps of Zn_(1-x)M_xO semiconductor in much better agreement with experimental data than the standard local exchange correlation functional. We find that the strong coupling between O 2p and Cu 3d or Ag Ad bands plays a key role in narrowing of band gaps and leading to the half-metallic behavior interpreted with the unique spatial distribution pattern between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO).