Levels of the charge transition of acceptor impurities in ZnO crystals. Calculations from the first principles.

The ab initio calculations of the charge state transition levels of impurity nitrogen and phosphorus defects in zinc oxide in the linear combination of atomic orbitals (LCAO) using the CRYSTAL09 program are carried out. It is shown that at a high concentration of defects (close to the location of defects), an underestimation of the energy of formation is observed in connection with a significant delocalization of the charge in the crystal cell. The inclusion of bias correction and defect-defective interaction improves the readings in comparison with the formation energy in a large supercell. The optical transition levels obtained by a direct calculation method confirm the experimental observation: impurity defects of nitrogen and phosphorus are deep acceptor centers and have high formation energy in a charged state and, therefore, are not an effective source of a hole charge. The obtained results are in good agreement with the previous theoretical works, in which other calculation methods were used and are capable of qualitatively describing the energy characteristics of the defects.