Electronic structure and properties of two-dimensional silicon dioxide

The electronic structure of two-dimensional silicon dioxide is studied using the projection augmented wave method within the density functional theory. The nonempirical calculations are significantly refined in the GW approximation. Nanofilms with a thickness of 0.35 to 1.76 nm, where the maximum number of atomic layer is 30, are considered. It is shown that the band gap strongly depends on the thickness of the two-dimensional nanocrystal and demonstrates three different types of behavior. This phenomenon is due to the shift of the Fermi level determined by the ratio of the numbers of Si and O atoms in the unit cell.