Atomic Structure and Electronic Structure of Si1-xGex and AlxGa1-xN: a Density Functional Theory Calculation

초록

To investigate the atomic and electronic structures of Si<inf>1-x</inf>Ge<inf>x</inf>and Al<inf>x</inf>Ga<inf>1-x</inf>N, special quasirandom structures were generated. Before structure optimization, the positions of the constituting atoms were altered to reproduce the bond lengths in Si, Ge, AlN, and GaN as close as possible. The total energy of the optimized structure through the first-principles density functional theory calculation was only 0.03 eV per atom smaller than that of the structure optimization. The lattice constants generally increased as the proportion of Ge or Ga increased. The bond length tended to maintain its value before the mixing of materials, so the change in bond length was smaller than the change in the lattice constants. The band gap of Al<inf>x</inf>Ga<inf>1-x</inf>N generally increased with the proportion of Al. In the hybrid density functional theory calculation, the band gap increased as the fraction of Hartree-Fock exchange in the functional increased. © 2022 The Korean Physical Society. All rights reserved.

키워드