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Twisted bilayer graphene (tBLG) has recently attracted growing interest due to its unique twist-angle-dependent electronic properties. The preparation of high-quality large-area bilayer graphene with rich rotation angles would be important for the investigation of angle-dependent physics and applications, which, however, is still challenging. Here, we demonstrate a chemical vapor deposition (CVD) approach for growing high-quality tBLG using a hetero-site nucleation strategy, which enables the nucleation of the second layer at a different site from that of the first layer. The fraction of tBLGs in bilayer graphene domains with twist angles ranging from 0° to 30° was found to be improved to 88%, which is significantly higher than those reported previously. The hetero-site nucleation behavior was carefully investigated using an isotope-labeling technique. Furthermore, the clear Moiré patterns and ultrahigh room-temperature carrier mobility of 68,000 cm 2  V −1  s −1 confirmed the high crystalline quality of our tBLG. Our study opens an avenue for the controllable growth of tBLGs for both fundamental research and practical applications. The synthesis of twisted bilayer graphene with controllable angles is challenging. Here, the authors devise a chemical vapor deposition approach using a hetero-site nucleation strategy that affords twist angles ranging from 0° to 30°.

Impurities produced during the synthesis process of a material pose detrimental impacts upon the intrinsic properties and device performances of the as-obtained product. This effect is especially pronounced in graphene, where surface contamination has long been a critical, unresolved issue, given graphene’s two-dimensionality. Here we report the origins of surface contamination of graphene, which is primarily rooted in chemical vapour deposition production at elevated temperatures, rather than during transfer and storage. In turn, we demonstrate a design of Cu substrate architecture towards the scalable production of super-clean graphene (>99% clean regions). The readily available, super-clean graphene sheets contribute to an enhancement in the optical transparency and thermal conductivity, an exceptionally lower-level of electrical contact resistance and intrinsically hydrophilic nature. This work not only opens up frontiers for graphene growth but also provides exciting opportunities for the utilization of as-obtained super-clean graphene films for advanced applications. The intrinsic properties of graphene and the resulting device performance are hindered by the impurities produced during the synthesis process. Here, the authors elucidate the origin of contaminations in CVD-grown graphene and devise a strategy towards the scalable production of ultra-clean graphene with >99% clean regions and low contact resistance.

The fast development of high-resolution electron microscopy (EM) demands a background-noise-free substrate to support the specimens, where atomically thin graphene membranes can serve as an ideal candidate. Yet the preparation of robust and ultraclean graphene EM grids remains challenging. Here we present a polymer- and transfer-free direct-etching method for batch fabrication of robust ultraclean graphene grids through membrane tension modulation. Loading samples on such graphene grids enables the detection of single metal atoms and atomic-resolution imaging of the iron core of ferritin molecules at both room- and cryo-temperature. The same kind of hydrophilic graphene grid allows the formation of ultrathin vitrified ice layer embedded most protein particles at the graphene-water interface, which facilitates cryo-EM 3D reconstruction of archaea 20S proteasomes at a record high resolution of ~2.36 Å. Our results demonstrate the significant improvements in image quality using the graphene grids and expand the scope of EM imaging. High-resolution electron microscopy requires robust and noise-free substrates to support the specimens. Here, the authors present a polymer- and transfer-free direct-etching method for fabrication of graphene grids with ultraclean surfaces and demonstrate cryo-EM at record high resolution.

The availability of graphene and other two-dimensional (2D) materials on a wide range of substrates forms the basis for large-area applications, such as graphene integration with silicon-based technologies, which requires graphene on silicon with outperforming carrier mobilities. However, 2D materials were only produced on limited archetypal substrates by chemical vapor deposition approaches. Reliable after-growth transfer techniques, that do not produce cracks, contamination, and wrinkles, are critical for layering 2D materials onto arbitrary substrates. Here we show that, by incorporating oxhydryl groups-containing volatile molecules, the supporting films can be deformed under heat to achieve a controllable conformal contact, enabling the large-area transfer of 2D films without cracks, contamination, and wrinkles. The resulting conformity with enhanced adhesion facilitates the direct delamination of supporting films from graphene, providing ultraclean surfaces and carrier mobilities up to 1,420,000 cm 2 V −1 s −1 at 4 K. Reliable transfer techniques are critical for the integration of 2D materials with arbitrary substrates. Here, the authors describe a method to transfer 4-inch and A4-sized defect-free graphene films onto rigid and flexible substrates with controllable conformal contact, leading to improved electrical properties and uniformity.

The integration of large-scale two-dimensional (2D) materials onto semiconductor wafers is highly desirable for advanced electronic devices, but challenges such as transfer-related crack, contamination, wrinkle and doping remain. Here, we developed a generic method by gradient surface energy modulation, leading to a reliable adhesion and release of graphene onto target wafers. The as-obtained wafer-scale graphene exhibited a damage-free, clean, and ultra-flat surface with negligible doping, resulting in uniform sheet resistance with only ~6% deviation. The as-transferred graphene on SiO 2 /Si exhibited high carrier mobility reaching up ~10,000 cm 2 V −1 s −1 , with quantum Hall effect (QHE) observed at room temperature. Fractional quantum Hall effect (FQHE) appeared at 1.7 K after encapsulation by h-BN, yielding ultra-high mobility of ~280,000 cm 2 V −1 s −1 . Integrated wafer-scale graphene thermal emitters exhibited significant broadband emission in near-infrared (NIR) spectrum. Overall, the proposed methodology is promising for future integration of wafer-scale 2D materials in advanced electronics and optoelectronics. Defect-free integration of 2D materials onto semiconductor wafers is desired to implement heterogeneous electronic devices. Here, the authors report a method to transfer high-quality graphene on target wafers via gradient surface energy modulation, leading to improved structural and electronic properties.

Bilayer graphene (BLG) is intriguing for its unique properties and potential applications in electronics, photonics, and mechanics. However, the chemical vapor deposition synthesis of large-area high-quality bilayer graphene on Cu is suffering from a low growth rate and limited bilayer coverage. Herein, we demonstrate the fast synthesis of meter-sized bilayer graphene film on commercial polycrystalline Cu foils by introducing trace CO 2 during high-temperature growth. Continuous bilayer graphene with a high ratio of AB-stacking structure can be obtained within 20 min, which exhibits enhanced mechanical strength, uniform transmittance, and low sheet resistance in large area. Moreover, 96 and 100% AB-stacking structures were achieved in bilayer graphene grown on single-crystal Cu(111) foil and ultraflat single-crystal Cu(111)/sapphire substrates, respectively. The AB-stacking bilayer graphene exhibits tunable bandgap and performs well in photodetection. This work provides important insights into the growth mechanism and the mass production of large-area high-quality BLG on Cu. Bilayer graphene (BLG) is promising for optoelectronic applications due to its tunable bandgap, but its large-area growth on Cu substrates is still challenging. Here, the authors demonstrate the fast synthesis of high-coverage meter-scale BLG on commercial Cu foils by introducing CO 2 during the growth.

Cryo-electron microscopy (cryo-EM) has been widely used to reveal the structures of proteins at atomic resolution. One key challenge is that almost all proteins are predominantly adsorbed to the air-water interface during standard cryo-EM specimen preparation. The interaction of proteins with air-water interface will significantly impede the success of reconstruction and achievable resolution. Here, we highlight the critical role of impenetrable surfactant monolayers in passivating the air-water interface problems, and develop a robust effective method for high-resolution cryo-EM analysis, by using the superstructure GSAMs which comprises surfactant self-assembled monolayers (SAMs) and graphene membrane. The GSAMs works well in enriching the orientations and improving particle utilization ratio of multiple proteins, facilitating the 3.3-Å resolution reconstruction of a 100-kDa protein complex (ACE2-RBD), which shows strong preferential orientation using traditional specimen preparation protocol. Additionally, we demonstrate that GSAMs enables the successful determinations of small proteins (<100 kDa) at near-atomic resolution. This study expands the understanding of SAMs and provides a key to better control the interaction of protein with air-water interface. Air-water interface hinders cryo-EM reconstruction and achievable resolution. Here, a superstructure called GSAMs is developed to alleviate the air-water interface effect and improve the efficiency of cryo-EM analysis.

Compared with single-layer two-dimensional (2D) materials, bilayer, trilayer, and few-layer 2D materials exhibit enhanced band structure tunability, improved electrical and thermal properties, and superior mechanical strength and barrier performance. However, the layer-controlled synthesis of 2D films with high layer number uniformity remains challenging, due to the difficulty in the additional layer nucleation and the effective realization of layer-by-layer growth. Herein, we report an edge-feeding synchronous epitaxial growth mode breaking the limit of traditional epitaxy theories. An efficient heterogeneous Cu–Cu 2 O catalyst is demonstrated, where graphene edge-surrounding Cu 2 O is crucial in precursor dissociation, atomic carbon diffusion, and edge energy reduction. The synchronous growth method can be generalized to the layer-controlled synthesis of 2–7-layer graphene films. Relying on this growth strategy, we successfully achieved the industrial-scale production of homogeneous A3-sized ABA-trilayer graphene films (42 × 30 square centimeters) with good mechanical properties and peeling-transferring intactness. Our method offers a robust strategy for the layer-controlled synthesis of 2D material films. Few-layer-thick 2D materials offer desirable electronic, thermal and mechanical properties, but their large-scale layer-controlled synthesis is still challenging. Here, the authors report an edge-feeding synchronous epitaxial growth method to synthesize homogeneous A3-sized graphene films with controlled thickness between 2 and 7 layers.

The scalable synthesis of high-quality graphite materials remains a formidable challenge due to the inherent trade-off between crystalline perfection and manufacturing efficiency. Existing forms of graphite, such as highly oriented pyrolytic graphite (HOPG) and Kish graphite, suffer from sluggish pyrolytic processes, limited carbon diffusion rates and energy-intensive protocols, often requiring several days for production. Here, we report a pulsed Joule heating-induced carburization (PJHIC) strategy that exploits transient non-equilibrium states to enable rapid carbon diffusion and segregation in metal substrates. By applying instantaneous thermal shocks ( > 1300 °C, > 300 °C/s heating rate) to solid carbon precursor-coated nickel and cobalt foils, we demonstrate the rapid carbon transport in bulk metals and achieve a vertical graphite growth rate of 730 nm/min, which is an order of magnitude faster than conventional methods. Cyclic temperature pulses further enable the synthesis of 1–5 μm-thick ABA-stacked graphite films with millimeter-scale grain sizes. The resulting rapid epitaxially grown graphite films exhibit a highly ordered crystalline structure and exceptional thermal conductivity (1314 W m –1 K –1 ), comparable to high-quality HOPG and Kish graphite. This work establishes a non-equilibrium synthesis paradigm for high-quality layered materials, bridging atomic-scale precision with industrial-scale manufacturing. Here, a pulsed Joule heating strategy for the synthesis of high-quality graphite is developed achieving a growth rate of up to 730 nm min -1 , an order of magnitude faster than conventional approaches, and producing large-area films with excellent thermal conductivity.

The fast growth of large single-crystalline graphene by chemical vapor deposition on Cu foil remains a challenge for industrial-scale applications. To achieve the fast growth of large single-crystalline graphene, understanding the detailed dynamics governing the entire growth process--including nucleation, growth, and coalescence is important; however, these remain unexplored. In this study, by using a pulsed carbon isotope labeling technique in conjunction with micro-Raman spectroscopy identification, we visualized the growth dynamics, such as nucleation, growth, and coalescence, during the fast growth of large single- crystalline graphene domains. By tuning the supply of the carbon source, a growth rate of 320 μm/min and the growth of centimeter-sized graphene single crystals were achieved on Cu foil.