Structural and electronic properties of hexagonal ZnO: A hybrid functional study

The role of stacked behavior in the structural and electronic properties of hexagonal ZnO (h-ZnO) has been studied by first-principles calculations based on Heyd–Scuseria–Ernzerhof (HSE) hybrid functional theory. Our calculated results show that the formation energies of four metastable stacked structures are at least higher by 0.8 eV/unit-cell than that of the most stable one. This can be explained by the typical ionic bonding between Zn and O atoms in h-ZnO. Furthermore, the band gaps of the different stacked structures are predicted to vary from 1.38 eV to 3.42 eV.

► Four metastable structures are unstable compared with the one with ground state.
► Different structures lead to the variation from 1.38 eV to 3.42 eV in the band gap.
► Lattice constants are also found to be strongly dependent on stacking in h-ZnO.