Investigation of vacancies effects on the electronic structure of α-Al2O3 crystal

In this study, the electron structure of the α-Al2</sub>O3</sub> rhombohedral graft has been investigated. The alpha-alumina structure belongs to the space group R3c and the rhombohedral with two units of formula (10 atoms) in the primary unit cell. Although the most widely used structure is hexagonal, it consists of 12 aluminum atoms and 18 atomic oxygen units, six units of formulas. The role of defects in the crystalline network, especially the vacancy defect, is investigated in this work. The band structure changes are evaluated in the absence of one of the O or Al atoms. The calculations showed that α-Al2</sub>O3</sub> has a direct transition at Γ, and the energy gap obtained from the density functional theory (DFT) method is 6.3 eV. Also, the depletion effect of O is higher than that of Al on the crystal electron structure: α-Al2</sub>O3</sub>:C, and is useful in increasing the response of this crystal as a detector.