Electronic Structure of Aluminum Oxide with Oxygen Vacancies

Abstract

Results of numerical calculations of the electronic structure of nonstoichiometric aluminum oxide with a concentration of oxygen vacancies of 6% have been presented. The calculations have been performed within the scope of the density-functional theory of the coherent-potential approximation with a disordered location of vacancies. It has been established that the presence of oxygen vacancies leads to the appearance of a peak in the density of states inside the energy gap and additional electronic states at the bottom of the conduction band, which gives a decrease in the energy gap to 2 eV. The simulation of the aluminum oxide of composition Al₂[O_0.98]₃\({\text{O}}_{{{\text{0}}{\text{.06}}}}^{{{\text{int}}\,{\text{erstitial}}}}\) with vacancies in the oxygen sublattice and oxygen atoms in interstices leads to a semiconducting character of the energy spectrum with a band gap of ~1 eV, which is formed between the p states of the impurity interstitial oxygen atoms and the s states of the vacancies.