Effects of epitaxial mismatch on the crystal orientation of Bi2Se3 across the amorphous to crystalline transition

The integration of Bi2Se3, a prototypical topological insulator, into heterostructures for spintronic, charge transfer, and proximity effect devices require atomically clean interfaces while mitigating interfacial diffusion. Here, we investigate how the interface affects the amorphous-to-crystalline transition in the topological insulator, Bi2Se3. Using in situ reflection high-energy electron diffraction (RHEED) and high-temperature X-ray diffraction (HTXRD), we show that structure and chemistry of the substrate serves as the primary driver of crystalline ordering. These properties are reflected in the degree of rotational disorder and the resulting grain size distributions, which can range from polycrystalline to near perfect epitaxy. Ultimately, this study elucidates the role of structural and chemical factors in amorphous-to-crystalline transition of Bi2Se3, providing a pathway toward the synthesis of high-quality interfaces for next-generation quantum devices.