Twin boundary formation at a grain-boundary groove during the directional solidification of InSb

We investigated twin boundary formation during directional solidification of the compound semiconductor InSb. We directly observed a groove formed at the junction of a solid-liquid interface and a sigma 9 grain-boundary by optical microscopy. When the depth of the grain-boundary groove reached about 100 mu m, rapid growth occurred to fill the groove. We found that two facet planes of the grain-boundary groove became twin boundary planes. Calculations of the change in free energy associated with nucleation at the grain-boundary groove indicates that the preferential twin nucleation occurs at the bottom of the groove, consistent with the direct observations in this study.

Automated summary

The study observed the formation of twin boundaries during directional solidification of compound semiconductor InSb. A groove formed at the junction of a solid-liquid interface and a sigma 9 grain-boundary, with rapid growth occurring to fill the groove. Calculations of the change in free energy associated with nucleation at the grain-boundary groove showed a preferential twin nucleation at the bottom of the groove, consistent with direct observations.