Electronic, magnetic and photocatalytic properties of Si doping in g-ZnO monolayer with point defects

Abstract

The electronic structures, magnetic properties, magnetic coupling and photocatalytic properties of Si-doping (4 × 4) graphene-like ZnO (g-ZnO) monolayer without or with defects including V O and V Zn have been calculated using the first-principles method. Si doping ZnO can increase the electronic state near Fermi level and introduce impurity state into the band gap due to P-type doping. The impurity state introduced by Si doping makes the system transition from NM to FM. The analysis of E f indicates that Si doping makes ZnO thin films easy to form V Zn . V O leads to two weakly bound Zn-4s electrons, V Zn leads to two weakly bound O-2p electrons, both of them can form impurity level near Fermi level, thus affecting the magnetic properties of g-ZnO monolayer. The analysis of magnetic coupling characteristics shows that the doping system undergoes a transition from NM to FM. Because the impurity state introduced by Si doping is beneficial to the excitation of electrons, Si doping can also reduce the gap between Fermi level and conduction band. The calculation result of optical properties shows that Si doping has strong absorption to visible light. • Si doping g-ZnO increases the electronic state of Fermi level and introduce impurity state into the band gap. • Si doping ZnO, V O and V Zn are the ferromagnetic origin of g-ZnO monolayer. • Si doping can reduce the gap between Fermi level and conduction band. • Si doping can improve the absorption of g-ZnO in the visible range.