The growth of compositionally uniform InAs1-xSbx bulk crystals remains a formidable challenge due to severe solute segregation and morphological instability under terrestrial conditions. Here, we report the successful growth of a single-crystalline InAs0.933Sb0.067 alloy (x = 6.7 mol%) on an InAs seed via the vertical gradient freeze method aboard the China Space Station. Crucially, microgravity enables diffusion-dominated solidification by suppressing buoyancy-driven convection. As a direct consequence, the crystal is free of macroscopic voids and striations, exhibits a tenfold reduction in dislocation density, and maintains Sb compositional uniformity (±0.5 mol%) over its entire ~11 mm diameter and ~2.5 mm growth length. Moreover, the microgravity-grown crystal outperforms its terrestrial counterpart in both crystalline quality and electrical properties. These findings highlight that microgravity provides a unique pathway to overcome the intrinsic limitations of ground-based growth, enabling crystal quality unattainable on Earth — with potential relevance to advanced optoelectronic applications.
Huang et al. (2026) studied this question.