Energy Gap Decrease in Cation Multidoped Aluminum Oxide

Abstract

The electronic structure of metal-doped α-Al 2 O 3 with the disordered distribution of multi-d-(Zr, Nb or/and Mo) and s-(Mg) impurities in the aluminum sublattice under the variation of their concentrations have been calculated using the coherent potential approximation method. Herein, an energy gap reduction due to appearance of new isolated occupied or empty Zr, Nb, and Mo d bands near the conduction band bottom of undoped α-Al 2 O 3 is shown. New multi dand s-doped α-Al 2 O 3 dielectrics Al 2ÀxÀy ZrðNb, MoÞ x Mg y O 3 with energy gap values of 7.1, 5.6, and 4.3 eV are found.