Electrochemical selective epitaxial growth of Au microstructures at wafer scale

Abstract Single-crystalline Au structures are an ideal building blocks for high-performance optoelectronic and electronic devices, and the precise alignment of Au functional units on large-area substrates serves as a core driver for advancing wafer-scale integration. However, the process faces two fundamental obstacles: (1) the deterministic positioning of pre-synthesized nanocrystals at target coordinates, and (2) morphological inhomogeneity accompanied by low fabrication yield in seed-mediated in-situ grown architectures. To date, the reliable fabrication of high-quality Au microstructures with precise spatial and crystallographic alignment, as well as chemically clean surfaces, on macroscopic substrates has not yet been realized. To address this critical challenge, we propose an electrochemical selective epitaxial deposition method based on surface state modulation, which enables the reliable fabrication of high-quality Au microstructures at the wafer scale. This mask-free growth strategy yields Au microstructures with atomically flat surfaces and a highly pure single crystallographic orientation. Our work provides a promising technical solution for the construction of high-performance optoelectronic integration platforms.