Wafer-scale growth of metallic films into single crystals is challenging due to large lattice mismatches and uncontrollable atomic stacking during deposition. Here, single-crystalline Ag(111) films are grown on atomically flat Cu(111) buffer layers using atomic sputtering epitaxy, despite the significant Ag/Cu lattice mismatch (about 13%). The mismatch strain is confined to the first Ag monoatomic interface layer and does not spread into the adjacent Ag layers. This effective strain relaxation occurs through regulated in-plane displacements of Ag atoms where Ag and Cu atoms meet periodically. Although the grain-boundary-free Ag thin films initially exhibited twin boundaries, we successfully demonstrated conditions that significantly reduced them—a feat considered challenging in thin film growth technology. The resulting films have inherently flat surfaces with occasional monoatomic steps, making them ideal for use as reflectors and plasmonic devices.

- Authors (Pusan National University)

· Su Jae Kim (Crystal Bank Research Institute)

· Tae-In Jeong (Department of Cogno-mechatronics Engineering)

· Seungchul Kim, Se-Young Jeong (Department of Cogno-mechatronics Engineering, Department of Optics and Mechatronics Engineering, Engineering Research Center for Color-Modulated Extra-Sensory Perception Technology)

- Title of original paper: Homoepitaxy-like heteroepitaxy via monolayer interface achieves grain-boundary-free ultraflat silver thin films

- Journal: Reports on Progress in Physics

- Web link: https://doi.org/10.1088/1361-6633/ae3e3d 

- Contact e-mail: syjeong@pusan.ac.kr