A transferable route to two-dimensional gate-all-around electronics

• A novel buffered van der Waals epitaxy technique enables wafer-scale synthesis of single-crystalline 2D GAA heterostructures. • The pre-deposited α-Bi2SeO5 buffer oxide effectively mitigates lattice and symmetry mismatch, enabling uniform Bi2O2Se growth. • In situ controlled oxidation transforms the top layer into β-Bi2SeO5, forming a high-k dielectric/semiconductor/high-k dielectric sandwich with atomically clean interfaces. • This scalable method overcomes limitations of existing techniques, paving the way for industry-compatible 2D GAA electronics.