Bottom‐Up‐Etching‐Mediated Synthesis of Large‐Scale Pure Monolayer Graphene on Cyclic‐Polishing‐Annealed Cu(111). Issue 8 (29th December 2021)

• Record Type: Journal Article
• Authors: Yao, Wenqian; Zhang, Jianing; Ji, Jie; Yang, He; Zhou, Binbin; Chen, Xin; Bøggild, Peter; Jepsen, Peter U.; Tang, Jilin; Wang, Fuyi; Zhang, Li; Liu, Jiahui; Wu, Bin; Dong, Jichen; Liu, Yunqi
• Is Part Of: Advanced materials. Volume 34:Issue 8(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-12-29
• Subjects: etching -- grain‐boundary migration -- monolayer graphene -- single‐crystal Cu(111); Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202108608
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Synthesis of large‐scale single‐crystalline graphene monolayers without multilayers involves the fabrication of proper single‐crystalline substrates and the ubiquitous formation of multilayered graphene islands during chemical vapor deposition. Here, a method of cyclic electrochemical polishing combined with thermal annealing, which allows the conversion of commercial polycrystalline Cu foils to single‐crystal Cu(111) with an almost 100% yield, is presented. A global "bottom‐up‐etching" method that is capable of fabricating large‐area pure single‐crystalline graphene monolayers without multilayers through selectively etching bottom multilayered graphene underneath large area as‐grown graphene monolayer on Cu(111) surface is demonstrated. Terahertz time‐domain spectroscopy (THz‐TDS) measurement of the pure monolayer graphene film shows a high average sheet conductivity of 2.8 mS and mean carrier mobility of 6903 cm 2 V −1 s −1 over a large area. Density functional theory (DFT) calculations show that the selective etching is induced by the much easier diffusion of hydrogen atoms than hydrocarbon radicals across the edges of the top graphene layer, and the simulated selective etching processes based on phase field modeling are well consistent with experimental observations. This work provides new ways toward the production of single‐crystal Cu(111) and the synthesis of pure monolayer graphene with high electronic quality. Abstract : A cyclic electrochemical polishing and thermal annealing approach that allows the effective conversion from commercial Cu to single‐crystal Cu(111) foils is reported. Using Cu(111), a general "bottom‐up‐etching" method is developed for producing pure monolayer graphene film with high and uniform electronic quality. This work provides new ways and mechanisms to address these key issues.