Coherent consolidation of trillions of nucleations for mono-atom step-level flat surfaces
Taewoo Ha, Yu‐Seong Seo, Teun-Teun Kim, Bipin Lamichhane, Young‐Hoon Kim, Su Jae Kim, Yousil Lee, Jong Chan Kim, Sang Eon Park, Kyung Ik Sim, Jae Hoon Kim, Yong In Kim, Seon Je Kim, Hu Young Jeong, Young Hee Lee, Seong‐Gon Kim, Young‐Min Kim, Jungseek Hwang, Se‐Young Jeong, Seong‐Gon Kim, Seong‐Gon Kim, Young‐Min Kim, Young‐Min Kim, Jungseek Hwang, Se‐Young Jeong
Abstract
Constructing a mono-atom step-level ultra-flat material surface is challenging, especially for thin films, because it is prohibitively difficult for trillions of clusters to coherently merge. Even though a rough metal surface, as well as the scattering of carriers at grain boundaries, limits electron transport and obscures their intrinsic properties, the importance of the flat surface has not been emphasised sufficiently. In this study, we describe in detail the initial growth of copper thin films required for mono-atom step-level flat surfaces (MSFSs). Deposition using atomic sputtering epitaxy leads to the coherent merging of trillions of islands into a coplanar layer, eventually forming an MSFS, for which the key factor is suggested to be the individual deposition of single atoms. Theoretical calculations support that single sputtered atoms ensure the formation of highly aligned nanodroplets and help them to merge into a coplanar layer. The realisation of the ultra-flat surfaces is expected to greatly assist efforts to improve quantum behaviour by increasing the coherency of electrons.