The effect of temperature gradient and ampoule velocity on the composition and other properties of Bridgman-grown indium antimonide

A systematic study of the role of the melt–solid interface position in determining the crystal quality of Bridgman-grown indium antimonide ingots is made. The crystals are grown under various conditions of imposed gradients and velocities. The gradient-to-velocity ratio $\wedge$ in the crystal is seen to move the interface position above or below the melting-point isotherm and this in turn affects crystal quality and grain structure. Post-growth investigations reveal that the growth takes place under off-stoichiometric conditions, for large as well as for small values of $\wedge$, undesirable for growth of high-quality homogeneous ingots of InSb. However, crystals grown under ‘near-equilibrium’ conditions are stoichiometric, show low defect density, improved grain structure and comparatively narrow rocking-curve width, with very high mobility