Layer-engineered large-area exfoliation of graphene

Abstract

The competition between quality and productivity has been a major issue for large-scale applications of two-dimensional materials (2DMs). Until now, the top-down mechanical cleavage method has guaranteed pure perfect 2DMs, but it has been considered a poor option in terms of manufacturing. Here, we present a layer-engineered exfoliation technique for graphene that not only allows us to obtain large-size graphene, up to a millimeter size, but also allows selective thickness control. A thin metal film evaporated on graphite induces tensile stress such that spalling occurs, resulting in exfoliation of graphene, where the number of exfoliated layers is adjusted by using different metal films. Detailed spectroscopy and electron transport measurement analysis greatly support our proposed spalling mechanism and fine quality of exfoliated graphene. Our layer-engineered exfoliation technique can pave the way for the development of a manufacturing-scale process for graphene and other 2DMs in electronics and optoelectronics.

Micromask Lithography for Cheap and Fast 2D Materials Microstructures Fabrication

“…The photos of the stages and the results of the lithography on few-layer graphene samples are shown in Figure 3 a–e. We used natural graphite and LLE method of mechanical exfoliation [ 31 ] to insulate mono- and few layers of graphene on oxidized Si (285 nm thermally grown wafer from Graphene Supermarket [ 32 ]). The Si wafer was heavily doped with boron to provide back-gating at the low temperatures.…”

Atomically Thin 2D van der Waals Magnetic Materials: Fabrications, Structure, Magnetic Properties and Applications

“…In this method, a selective metal film was directly evaporated on bulk graphite precleaved on blue tape and then large-area graphene with a selected number of layers can be exfoliated easily. This LEE approach paves the way for the development of a manufacturing-scale process for future applications based on a 2D heterostructure (Figure 8c) [180].…”

“…(c) Schematic illustration of the LEE large-area graphene exfoliation technique. Reused with permission from[180]. (d) Photographs of the dispersions of MoS2 (in N-methyl-pyrrolidone (NMP)), WS2 (in N-methyl-pyrrolidone (NMP)), and BN (in isopropanol (IPA)).…”

Silicon/2D-material photodetectors: from near-infrared to mid-infrared

“…Fortunately, it is shown that large-area mechanical exfoliation of graphene with controlled thickness can be achieved, as demonstrated recently in ref. 148 , showing high potential for the device development in the future. In order to develop high-performance Si/2DM PDs, more efforts at the material level are desired for the interface engineering, including contact engineering 149 , doping engineering, and strain engineering 12 , as shown in Fig.…”