A theoretical study on various models for the domain boundaries in epitaxial GaN films

Abstract

Various domain boundaries that are found in epitaxial Wurtzite GaN films were studied by molecular dynamics simulation. The Ewald summation algorithm and Keating potential model are adopted to calculate the longrange Coulomb interaction and the short-range bonding force in the semiconductor system, respectively. The research results show that the domain formation energies of (1100) and (1120) boundaries are significantly different. The latter ones have general quite higher formation energies than the formers. The like-atom (i.e. atoms of the same kind) bonding domain boundaries (LABDB) have higher formation energies than their counterparts of unlike-atom (i.e. atoms of different kinds) bonding domain boundaries (UABDB) in all GaN (1100) and (1120) interfaces. The UABDB structures are all stable while most of the LABDB are unstable. The advantage and the limitation of Keating potential model in Molecular Dynamics simulation for covalent crystal are discussed. PACS: 61.70; 61.16.D; 68.55.LnGallium nitride (GaN) attracts extensive research interests both in science and in industry for it is an important material in the manufacture of photoelectric device, such as blue/green light-emitting diode, laser diode, etc. The successful application of the material may cause revolutionary changes of the human world in illumination and imaging apparatuses. A significant character of GaN is that it can still give high-efficiency luminescence even under a high density of crystal defects. This phenomenon seems in paradox with the common opinion that lattice defects introduce nonradiative recombination centres in III-V semiconductor and the recombination centres reduce the efficiency and lifetime of the photoelectric devices. The puzzle imposes an urgent demand for an in-depth study of the defect structures and their roles in the light-emission process of GaN crystal.

Sputtering Yield as a Function of Incident Ion Energy and Angle in Wurtzite-Type GaN Crystal

“…This value is in good agreement with the value of 1.147 found in ref. 10 and the the value of 1.16 found for the screened effective charge in ref. 11.…”

Point Defects Induced by Physical Sputtering in Wurtzite-Type GaN Crystal

“…The partial charge of 1.15 is in good agreement with the value of 1.147 in ref. 19 and the value of 1.16 in ref. 20.…”

Systematic approach to developing empirical interatomic potentials for III–N semiconductors

“…Despite the importance of III-N semiconductors, very little systematic attempt has been made to obtain their empirical interatomic potentials. Most of the potentials are developed for individual materials such as BN 1,2) and GaN [3][4][5][6] using different formulations. This is because of the difficulty in universally reproducing the relative stability among 3-fold coordinated hexagonal (Hex favored by BN), 4-fold coordinated zinc blende (ZB commonly appeared in III-V semiconductors), and wurtzite (WZ stable in AlN, GaN, and InN) structures.…”