In-situ observation of instability of a crystal–melt interface during the directional growth of pure antimony

摘要

The instability of a crystal–melt interface during the directional growth of pure antimony was studied using an in-situ observation technique. The morphology of the crystal–melt interface was planar at a low growth velocity, while the interface transitioned to wavy and then zig-zag faceted at 60 μm s?1. Calculating the thermal field at the crystal–melt interface using a diffusion equation showed that the temperature gradient in the melt becomes negative when the moving velocity of the interface is higher than 52 μm s?1. These results demonstrate that perturbations introduced into the planar interface are amplified by a negative temperature gradient and these amplified perturbations result in zig-zag facets.