Nucleation of threading dislocations in atomistic simulations of strained layer epitaxy of III-nitrides

0579395 - ÚFM 2025 RIV GB eng J - Článek v odborném periodiku
Gröger, Roman - Fikar, Jan
Nucleation of threading dislocations in atomistic simulations of strained layer epitaxy of III-nitrides.
Acta Materialia. Roč. 264, Jan (2024), č. článku 119570. ISSN 1359-6454. E-ISSN 1873-2453
Grant CEP: GA TA ČR(CZ) FW01010183
Institucionální podpora: RVO:68081723
Klíčová slova: Epitaxy * Misfit * Atomistic simulation * Threading dislocation * Misfit dislocation * Tersoff potential
Obor OECD: Condensed matter physics (including formerly solid state physics, supercond.)
Impakt faktor: 9.4, rok: 2022
Způsob publikování: Omezený přístup
https://www.sciencedirect.com/science/article/pii/S1359645423008996?via%3Dihub

The early stage of heteroepitaxial growth of wurtzite III-nitrides on lattice-mismatched substrates produces
epitaxial strain that is relieved by nucleating a network of misfit dislocations. However, these epilayers contain
also a large density of threading dislocations that are nearly perpendicular to the interface, despite the fact
that they do not relieve the epitaxial strain. To shed light onto the mechanism of nucleation of threading
dislocations, we employ atomistic simulations to explore the heteroepitaxy between a GaN nanoisland and a
rigid substrate whose lattice parameter is adjusted to produce the desired misfit. We observe that the ends of
misfit dislocations experience large image forces that pull them toward the pyramidal facets of the nanoisland.
This results in bending of the terminating ends of misfit dislocations which constitute segments of threading
dislocations. The spacing of these threading dislocations would increase (and thus their density decrease) if
the epitaxial growth could be manipulated such that the film was deposited in a layer-by-layer fashion.

Trvalý link: https://hdl.handle.net/11104/0352664