Dirac Fermion Kinetics in 3D Curved Graphene

Abstract

3D integration of graphene has attracted attention for realizing carbon‐based electronic devices. While the 3D integration can amplify various excellent properties of graphene, the influence of 3D curved surfaces on the fundamental physical properties of graphene has not been clarified. The electronic properties of 3D nanoporous graphene with a curvature radius down to 25–50 nm are systematically investigated and the ambipolar electronic states of Dirac fermions are essentially preserved in the 3D graphene nanoarchitectures, while the 3D curvature can effectively suppress the slope of the linear density of states of Dirac fermion near the Fermi level are demonstrated. Importantly, the 3D curvature can be utilized to tune the back‐scattering‐suppressed electrical transport of Dirac fermions and enhance both electron localization and electron–electron interaction. As a result, nanoscale curvature provides a new degree of freedom to manipulate 3D graphene electrical properties, which may pave a new way to design new 3D graphene devices with preserved 2D electronic properties and novel functionalities.

3D Continuously Porous Graphene for Energy Applications

“…into account the electron trajectories in the complex 3D porous structures (Figure 7c). [22,24,35,101] The latter is comparable to the electron mobility of high-quality CVD-grown 2D graphene. Therefore, the 2D graphene can be effectively scaled to a largesized 3D architecture without compromising its remarkable 2D electronic properties and high electron mobility.…”

“…The electric transport property measurements of the 3D nanoporous graphene show an apparent electron mobility of 100–500 cm 2 V −1 s −1 by considering the nanoporous graphene as a uniform 3D conductor, and an intrinsic electron mobility of 5000–10000 cm 2 V −1 s −1 by taking into account the electron trajectories in the complex 3D porous structures (Figure 7c). [ 22,24,35,101 ] The latter is comparable to the electron mobility of high‐quality CVD‐grown 2D graphene. Therefore, the 2D graphene can be effectively scaled to a large‐sized 3D architecture without compromising its remarkable 2D electronic properties and high electron mobility.…”

“…Such “ideal 3D graphene” with the periodic or pseudo‐periodic minimal surfaces is envisioned to retain all of the unique properties of 2D graphene while also allowing for the addition of structural features such as bicontinuous porosity, 3D curvature, and 3D pseudo‐periodicity to enable new functionalities. [ 22,23 ] While the “ideal 3D graphene” is not yet a reality, several 3D continuously porous graphene materials have been synthesized that exhibit the aforementioned desirable properties in part. The most representative example is the 3D nanoporous graphene synthesized by dealloyed nanoporous metal‐based chemical vapor deposition (CVD).…”

2D MoS2 Heterostructures on Epitaxial and Self‐Standing Graphene for Energy Storage: From Growth Mechanism to Application

“…Nanoporous Graphene Sponge Preparation: The NPG was synthesized through a typical CVD method using a nanoporous Ni film (30-35 μm) as substrate. [95][96][97][98][99] First, the nanoporous Ni film was prepared by dealloying a Ni 30 Mn 70 (at%) alloy film (50 μm) in 1.0 m (NH 4 ) 2 SO 4 aqueous solution at 50 °C for 12 h. After dealloying, the samples were rinsed thoroughly with water and ethanol, and then dried in vacuum for 12 h under 25 °C. Second, the as-prepared Ni substrates loaded on a corundum plate were inserted into the center of a quartz tube (ϕ30 × ϕ27 × 1000 mm) furnace and annealed at 800 °C under a mixed ) rate capability at current densities from 30 to 600 mA g −1 , c) comparison of the specific capacity of MoS 2 /NPG-280 anode with several anodes prepared using MoS 2 and carbon materials at respective current densities (R1, this work; R2, MoS2-rGO; [76] R3, rGO; [47] R4, few layered graphene; [70] R5, F-doped graphene foam; [75] R6, MoS 2 ; [26] R7, MoS2/N doped graphene; [39] R8, MoS2-N-doped carbon sponge; [77] R9, MoS2-MXene; [68] R10, MoS2@hollow porous carbon-sphere composite; [72] R11, MoS2/N-doped-C hollow tubes; [78] R12, MoS 2 /Sb encapsulated N-doped graphene; [79] R13, MoS 2 -WS 2 -C; [80] R14, Mosaic Red Phosphorus/MoS2 hybrid; [81] R15, MoS 2 @C hierarchical microspheres; [82] R16, MoS 2 Nanotubes; [83] R17, MoS 2 clusters inside a hollow tubular carbon skeleton (HTCS); [73] R18, 1 T-MoS 2 /MoO x @NC), [74] (d) galvanostatic cycling capacity and coulombic efficiency at 60 mA g −1 .…”

“…The NPG was synthesized through a typical CVD method using a nanoporous Ni film (30–35 µm) as substrate. [ 95–99 ] First, the nanoporous Ni film was prepared by dealloying a Ni 30 Mn 70 (at%) alloy film (50 µm) in 1.0 m (NH 4 ) 2 SO 4 aqueous solution at 50 °C for 12 h. After dealloying, the samples were rinsed thoroughly with water and ethanol, and then dried in vacuum for 12 h under 25 °C. Second, the as‐prepared Ni substrates loaded on a corundum plate were inserted into the center of a quartz tube (φ30 × φ27 × 1000 mm) furnace and annealed at 800 °C under a mixed atmosphere of Ar (99.99%, 200 sccm) and H 2 (99.99%, 100 sccm) for 3 min as reduction pre‐treatments.…”