Study on the interface electronic properties of AlN(0001)/ β-Ga2O3(100)

Abstract

Using density functional theory, the electronic properties of six different AlN(0001)/β-Ga2O3(100) are analyzed. Atomic relaxation, formation energy, binding energy, electron distribution, and band offsets are investigated. The analysis shows that, for the B-Al, B-N, and CN models, not only the thermodynamic stability is high but also interface bonding is relatively strong. Furthermore, after undergoing structural optimization, interface spacing is reduced significantly. The charge analysis shows that significant charge transfer occurs between the three models, and Al-O, NO as well as Ga-N bonds are formed between the interface atoms. The obtained conduction-band offsets (CBOs) of the three models are 1.7 eV, 1.86 eV, and 1.85 eV, which are very similar to the experimentally obtained values. The study of band structure shows that the heterostructure has the theoretical basis of producing 2DEG with high surface charge density. However, for the A-Al, A-N, and C-Al models, the three models are either thermodynamic unstable or associated with weak interface bonding. Furthermore, relaxation mainly occurs in the horizontal direction, and the atoms at the interface are arranged in the form of diluted- and dense-patches. There is no clear charge transfer and chemical bond between the interface atoms, which are bound together via physical adsorption.