Interface-Driven Faceted Epitaxy of GaAs on Si(331) with Self-Organized Nanocorrugation and Anisotropic Emission

We report a lithography-free route to grow faceted GaAs on high-index Si(331) that yields a self-organized, nanocorrugated interface and in-plane optical anisotropy. By combining a controlled Ga pre-exposure with low-rate GaAs deposition, the surface evolves towards a periodic morphology consistent with alternating {111}/{110} micro- facets. Reflection high-energy electron diffraction, atomic force microscopy, and high- resolution X-ray diffraction/reciprocal space mapping together reveal long-range ordering with characteristic periods in the tens-of-nanometres range and narrow reciprocal-space features indicative of good crystalline quality. Polarization-resolved μ−PL reveals anisotropic emission aligned with the in-plane symmetry breaking imposed by the faceted template. We quantify corrugation period, amplitude, and local facet an- gle across multiple wafers and areas, and identify a reproducible growth window that reliably produces the ordered state. By replacing top-down patterning with interface- driven ordering, this approach provides a practical, scalable pathway toward monolithic GaAs-on-Si integration, where built-in polarization selectivity and directional coupling are desirable for on-chip photonics. The results establish a reproducible growth recipe and quantifiable structure–property links directly applicable to polarization-sensitive emitters and anisotropy-engineered photonic elements on silicon.