Formation energy of N impurities in ZnO calculated using the PBE functional as function of the oxygen chemical potential.
Orbital-projected density of states of a neutral NO impurity in ZnO, calculated in the Zn36O35N supercell (left column) and in the Zn96O95N supercell (right column). Vertical dashed and solid lines indicate the band gap of the host material and the Fermi level ɛF of the system, respectively. The energy is expressed with respect to the corresponding vacuum level in each method. The charge densities of the N impurity in the 4 × 4 × 3 supercell (Zn96O95N) are presented using the M-1 (PBE) and the M-6 (+U) methods. The green and white isosurfaces represent the charges of occupied and unoccupied states at 0.3e, respectively. The charge of occupied states is integrated from E v to ɛF and the charge of unoccupied states is integrated from ɛF to E c . The arrows show the c-direction of the cell.
Orbital-projected density of states of the neutral NO impurity calculated in the ZnO (Zn36O35N) supercell using hybrid density functionals.
ɛ(+ /0) and ɛ(0/ −) charge transfer levels of the NO impurity in ZnO. The band edges are given with respect to the vacuum level in (a), and are taken directly from the (generalised) Kohn-Sham levels in (b).
Details of the employed methods. a PBE is the lattice constant optimized with the PBE functional.
Crystal properties (unit cell volume Vcell, band gap E g , and dielectric constant ɛ) of ZnO, formation energy of the neutral NO impurity, and charge ɛ(0/ −) level using various methods. The formation energy is calculated under oxygen-rich conditions, as described in the text. The details of the methods are found in Table I . The last row contains experimental data; n.a. stands for “not available.”
The properties of the NO impurity in Zn36O36, Zn96O96, and Zn288O288 supercells.
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