First principle calculations study of AlN surface terminal structure evolution under different conditions

Abstract

The surface structure and properties of aluminum nitride (AlN) play an important role in many applications. Using the first principle calculations method, we analyzed the surface terminal structure of AlN and its evolution under different conditions by determining the surface energy, adsorption energy, and evaporation energy of the Al and N terminals on the AlN(0001) surface. Our results show that the reason why the N terminal is less stable than the Al terminal is not only because of its high surface energy but also because its adsorption performance is extremely sensitive to the adsorption position. The surface N atoms combine to form N2 molecules that escape during the evaporation process at high temperature. After surface N atoms escape, the AlN surface structure reconstitutes to form a 3×3−R30° hexagonal closest packing (HCP)–like structure, and the energy barrier for the reconstructing process is 3.2 eV. This shows that the structure and form of the AlN(0001) terminals depend on the environmental conditions.

Research on the Stability of Different Polar Surfaces in Aluminum Nitride Single Crystals

“…The surface energy of the Al and the N-polar surface of AlN crystal were calculated by this method to be 316 meV/Å 2 and 350 meV/Å 2 , respectively. indicating the smaller Al-polar surface energy than the N-polar surface [29,31], as well as a better stability of the Al-polar surface than the N-polar surface.…”

“…In order to calculate the surface energy of the polar surface of AlN wurtzite crystal, S. Sun et al have established the Al terminal and N terminal surface models whose Al and N atoms do not combine in a stoichiometric ratio [31]. The surface energy of the Al and the N-polar surface of AlN crystal were calculated by this method to be 316 meV/Å 2 and 350 meV/Å 2 , respectively.…”

An investigation using DFT into the impact of hydrogen on oxygen migration processes during aluminum anodization

“…29 Density functional theory (DFT) has been the most effective tool in condensed matter physics for computing electronic structure and its properties since its inception in the 1960s, when it was initially used to derive the well-known Kohn-Sham (KS) equation under the local density approximation (LDA). Numerous atomic and molecular physics puzzles, including those involving catalytic active sites, 30,31 geometric structure, 32,33 and material electronic structure properties, 34,35 can be resolved with DFT. DFT is also commonly used to calculate the functions of the ions during chemical reactions, 36,37 as it can accurately reveal reaction pathways clearly.…”