The Way towards Ultrafast Growth of Single-Crystal Graphene on Copper

Abstract

The exceptional properties of graphene make it a promising candidate in the development of next-generation electronic, optoelectronic, photonic and photovoltaic devices. A holy grail in graphene research is the synthesis of large-sized single-crystal graphene, in which the absence of grain boundaries guarantees its excellent intrinsic properties and high performance in the devices. Nowadays, most attention has been drawn to the suppression of nucleation density by using low feeding gas during the growth process to allow only one nucleus to grow with enough space. However, because the nucleation is a random event and new nuclei are likely to form in the very long growth process, it is difficult to achieve industrial-level wafer-scale or beyond (e.g. 30 cm in diameter) single-crystal graphene. Another possible way to obtain large single-crystal graphene is to realize ultrafast growth, where once a nucleus forms, it grows up so quickly before new nuclei form. Therefore ultrafast growth provides a new direction for the synthesis of large single-crystal graphene, and is also of great significance to realize large-scale production of graphene films (fast growth is more time-efficient and cost-effective), which is likely to accelerate various graphene applications in industry.

Keywords: CVD; Cu foil; single crystal; ultrafast graphene growth.

Figure 1

The solubility of carbon in several transition metals at 1000 °C.76

Figure 2

Graphene domain size versus growth rate on Cu foil in 2009–2016.31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54

Figure 3

Schematics of graphene growth with (a) low and (b) ultrahigh growth rate.

Figure 4

Schematic illustration of the way to improve the graphene growth.

Figure 5

The graphene growth by attachment of dissociated C onto graphene domain edge versus the H₂ etching by detachment of C from graphene domain edge.

Figure 6

a–c) Schematic illustration and Density‐Functional‐Theory (DFT) calculated energy barrier for the CH4 dissociation with and without oxygen on Cu surface. Reproduced with permission.36 2016, Nature Publishing Group. d–f) Atomic‐scale schematics of graphene edge structure on Cu surface with and without oxygen and DFT calculated energies of different configurations of H. Reproduced with permission.35 2013, American Association for the Advancement of Science. g) Summary of Climbing Image‐Nudged Elastic Band (CI‐NEB) calculations of CH4 full dissociation reactions with and without oxygen on Cu surface. The energy barriers of the decomposition reactions with oxygen (golden line), are 0.62, 1.29, 0.53 and 1.11 eV, respectively; the energy barriers of reactions without oxygen (purple line) are 1.57, 1.37, 0.59, and 1.47 eV, respectively.