Atomistic approach to simulate kink migration and kink-pair formation in silicon: The kinetic activation-relaxation technique

S.N.H. Eliassen (1) , J. Friis (2) , I.G. Ringdalen (2) , N. Mousseau (3) , Mickael Trochet (4) , Y. Li (1)

1 NTNU - Norwegian University of Science and Technology [Trondheim]
2 SINTEF Industry
3 UdeM - Université de Montréal
4 SRMP - Service de recherches de métallurgie physique

The energy conversion efficiency of solar cells based on multicrystalline silicon is greatly deteriorated by dislocations. However, an in-depth understanding on the dislocation motion dynamics down to atomic scale is still lacking. In this paper, we propose a novel atomistic approach to simulate the kink migration and kink-pair formation which govern dislocation motion in silicon, namely the kinetic activation-relax technique (k-ART). With this method, long timescale events can be simulated and complex energy landscapes can be explored. Four mechanisms for kink migration are observed, with total activation energy of 0.16, 0.25, 0.32, and 0.25 eV. New nontrivial kink structures that participate in kink migration are identified due to the open-ended search algorithm for saddle points in k-ART. In addition, a new pathway for kink-pair formation, with a minimum activation energy of 1.11 eV is discovered. The effect of shear stress on kink migration is also investigated. It shows that shear stress shifts the energy barriers of available events to lower energies, resulting in a change of the preferred kink-migration mechanism and a reduction of kink-pair formation energy.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

S.N.H. Eliassen, J. Friis, I.G. Ringdalen, N. Mousseau, Mickael Trochet, et al.. Atomistic approach to simulate kink migration and kink-pair formation in silicon: The kinetic activation-relaxation technique. Physical Review B, 2019, 100, pp.155305. ⟨10.1103/PhysRevB.100.155305⟩. ⟨cea-03746198⟩