Revisiting the structures and energies of silicon 〈110〉 symmetric tilt grain boundaries

Atomistic simulations of 18 silicon 〈110〉 symmetric tilt grain boundaries are performed using Stillinger Weber, Tersoff, and the optimized Modified Embedded Atom Method potentials. We define a novel structural unit classification through dislocation core analysis to characterize the relaxed GB structures. GBs with the misorientation angle θ ranging from 13.44° to 70.53° are solely composed of Lomer dislocation cores. For GBs with θ less than but close to 70.53°, GB ‘step’ appears and the equilibrated states with lowest GB energies can be attained only when such GB ‘step’ is located in the middle of each single periodic GB structure. For the misorientation angles in the range of 93.37° ≤ θ ≤ 148.41°, GB structures become complicated since they contain multiple types of dislocation cores. This work not only facilitates the structural characterization of silicon 〈110〉 STGBs, but also may provide new insights into mirco-structure design in multicrystalline silicon.