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VOLUME 114 (2021) | ISSUE 5 |
PAGE 346
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Influence of cation impurities and both cation and anion nonstoichiometry on aluminum oxide energy gap width
V. M. Zainullina, M. A. Korotin+
Institute of Solid State Chemistry, Ural Branch of Russian Academy of Sciences, 620990 Yekaterinburg, Russia +M. N. Mikheev Institute of Metal Physics, Ural Branch of Russian Academy of Sciences, 620108 Yekaterinburg, Russia
Abstract
Using the Coherent Potential Approximation, the electronic structure of
α- Al2O3 (corundum) with various concentrations of mono and
multi d- (Zr, Nb, Mo), p- (Ga, Sn) impurities in aluminum
sublattice and vacancies in both aluminum and oxygen sublattices was
calculated. It was found that an energy gap width reduction occurs due to
specific filling of both new Zr, Nb, Mo d bands and oxygen vacancy
s peak which appear in the gap of undoped α- Al2O3.
This is in good agreement with experimental data. New d- and
p-doped compositions including those nonstoichiometric in aluminum
sublattice with energy gap values lying in the interval from 4.3 to
8.1 eV are proposed for advanced electronic devices. Three doped
compounds having 0.4-2.1 eV energy gap widths with alternation of
nonstoichiometric sublattices and number of d- and p-
impurities in aluminum sublattice are found. They can be considered as
promising materials for solar cells and photodiods.
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