Crystal Growth and Steady‐State Segregation under Zero Gravity: InSb

It was established that ideal, diffusion‐controlled, steady‐state segregation, never accomplished on earth, was achieved during the growth of Te‐doped crystals in Skylab. Surface tension effects led to nonwetting conditions under which free surface solidification took place in confined geometry. It was further found that, under forced contact conditions, surface tension effects led to the formation of surface ridges (not previously observed on earth) which isolated the growth system from its container. In addition, it was possible, for the first time, to identify unambiguously: the origin of segregation discontinuities associated with facet growth, the mode of nucleation and propagation of rotational twin boundaries, and the specific effect of mechanical‐shock perturbations on segregation. The results obtained prove the advantageous conditions provided by outer space. Thus, fundamental data on solidification thought to be unattainable on earth because of gravity‐induced interference are now within reach.