Colossal grain growth yields single-crystal metal foils by contact-free annealing

Abstract

Single-crystal metals have distinctive properties owing to the absence of grain boundaries and strong anisotropy. Commercial single-crystal metals are usually synthesized by bulk crystal growth or by deposition of thin films onto substrates, and they are expensive and small. We prepared extremely large single-crystal metal foils by “contact-free annealing” from commercial polycrystalline foils. The colossal grain growth (up to 32 square centimeters) is achieved by minimizing contact stresses, resulting in a preferred in-plane and out-of-plane crystal orientation, and is driven by surface energy minimization during the rotation of the crystal lattice followed by “consumption” of neighboring grains. Industrial-scale production of single-crystal metal foils is possible as a result of this discovery.

Adlayer‐Free Large‐Area Single Crystal Graphene Grown on a Cu(111) Foil

“…Growth of Graphene on Cu(111) and As‐Received Polycrystalline Cu Foils : CVD growth of graphene was performed on polycrystalline and single crystal Cu(111) foils. The single crystal Cu(111) foil was made from the polycrystalline Cu foil by our contact‐free annealing method (Figure S1, Supporting Information) . Three different conditions for the growth of a continuous graphene film on either the Cu(111) single crystal foil or the polycrystalline Cu foil were performed with H 2 /CH 4 ratios in the range 100:1 to 1000:1, and a pressure during growth in the range of 2.0 to 30.0 Torr ( Figure a,b; Figure S2, Supporting Information).…”

“…We report here the growth of large‐area adlayer‐free single layer, single crystal graphene films on lab‐made single crystal Cu(111) foils that were made from polycrystalline Cu foils by annealing for a long time in a mixed hydrogen and argon atmosphere . By contrast, graphene films with adlayers were always obtained using as‐received commercial polycrystalline Cu foils under the same growth conditions.…”

Fermi velocity renormalization in graphene probed by terahertz time-domain spectroscopy

“…[22,27] Commercially available CVD grown graphene (Graphenea) on copper substrate was transferred onto PEN substrates by etching transfer. [28,29] Graphene on SiO 2 was fabricated from CVD growth of graphene on Cu(111) foils [30] prepared by contact-free annealing [31] and subsequent bubbling transfer [32]. Electrical parameters σ DC , n and µ of graphene in all these substrates measured in this [22] and regions of high mobility of charge carriers in graphene supported on PEN [29] (despite our measurements are undertaken in larger spatial regions and under ambient conditions).…”

Modified Engineering of Graphene Nanoribbons Prepared via On‐Surface Synthesis

“…Furthermore, single‐crystalline Cu(111) substrates are more accessible than Au(111) and Ag(111) substrates. Producing large‐area single‐crystalline Cu(111) as substrates for graphene growth has been reported by some groups recently . By using Cu(111) as a substrate, GNRs from DBBA molecules may form at lower temperature on Cu(111) compared with that on Au(111) surface .…”

“…However, like Au substrate, its exorbitant price and small‐size single‐crystalline Ag substrate limit the mass production of GNRs. On the other hand, Cu substrate hold an advantage of the large‐area production of its various single crystalline, which provides an opportunity to mass production of GNRs. Furthermore, the dehalogenation occurred at room temperature allowed the formation of polymer chains and even GNRs at lower temperature.…”