Atomic simulations of dislocation interactions with coincidence site lattice boundaries in silicon

With low production costs and high efficiency, multicrystalline silicon (mc-Si) is widely used in solar cell applications. The crystallization of mc-Si introduces defects which deteriorates the conversion efficiency. Characterization studies suggests that dislocations are positioned at coincidence site lattice (CSL) boundaries. However, such studies are often performed post mortem, thus, the dynamics are not captured. Therefore, an atomistic description of the interactions between the dislocation and CSL boundaries is lacking. To fill in the missing gap, the kinetic Activation-Relaxation Technique (k-ART) has been utilized to simulate the interaction between dislocations and various CSL boundaries. With k-ART, an extensive exploration of the energy landscape is conducted, resulting in full atomistic details of the energy pathways of the interactions, achievable on timescales relevant to experimental studies. In this work, models based on high resolution Transmission Electron Microscope images of the Σ3, Σ9 and Σ27 grain boundaries have been constructed. A pure screw dislocation is placed at various distances from the boundary, and investigated with k-ART. We present here a full picture of the energy landscape for a dislocation to diffuse to the grain boundary and the critical stress required to re-emit the dislocation from the boundary.