Twisted Bilayer Graphene Properties and Characterization

Twisted bilayer graphene (tBLG) consists of two monolayers of graphene rotated by a defined angle, giving rise to a moiré superlattice that profoundly alters electronic, optical and mechanical behaviour. Variation of the twist angle allows the tuning of van Hove singularities in the density of states, interlayer coupling strength and band structure, enabling phenomena such as correlated insulating states, unconventional superconductivity and strong light–matter interactions. Growth methods have evolved from mechanical stacking towards scalable techniques including chemical vapour deposition with controlled nucleation sites and in situ twistable devices. Characterization relies on a combination of spectroscopic and imaging tools—Raman spectroscopy for probing phonon and electronic resonances, angle‐resolved photoemission for band mapping, scanning near-field optical microscopy for nanoscale optical contrast, atomic force microscopy for lattice orientation and transmission electron microscopy for atomic registry. These advances support applications in tunable photodetectors, nonlinear optics, quantum simulation platforms and next-generation electronic devices, highlighting the global significance of twist-engineered two-dimensional materials.

Research from Nature Portfolio

Recent studies have demonstrated an in situ twistable bilayer platform in which the rotation between graphene monolayers can be continuously adjusted within a single device. Angle tuning is confirmed by atomic force microscopy for lattice orientation, scanning near-field optical microscopy to image moiré domain walls and resonant Raman spectroscopy to track enhanced vibrational modes. This approach enables systematic exploration of angle-dependent phenomena without the need for multiple samples. In parallel, a hetero-site nucleation strategy has been developed to grow large-area twisted bilayer graphene via chemical vapour deposition. By promoting second-layer nucleation at distinct surface sites, the yield of domains spanning a broad twist-angle range (0°–30°) rises to over 85 per cent. Isotope-labelling experiments reveal precise control over layer formation, while high-resolution imaging and transport measurements confirm ultrahigh carrier mobility and clear moiré patterns, laying the foundation for scalable production of high-quality tBLG for fundamental studies and device integration.

Twisted Bilayer Graphene Properties and Characterization publication trend

The graph below shows the total number of articles in twisted bilayer graphene properties and characterization across all publications each year (not limited to Nature Index journals).

Technical terms

Twist angle: The relative rotational orientation between two graphene layers that determines the moiré superlattice and modulates electronic and optical properties.

Moiré pattern: The interference pattern formed by superposing two periodic lattices, giving rise to new periodicities and emergent phenomena in tBLG.

Van Hove singularity: A feature in the electronic density of states where the derivative diverges, leading to enhanced optical absorption and electron correlation effects at specific energies.

Exciton: A bound state of an electron and a hole whose binding energy and dynamics are influenced by interlayer coupling in twisted graphene.

Chemical vapour deposition (CVD): A fabrication technique for producing large-area two-dimensional materials under controlled temperature and gas environments.

Raman spectroscopy: A non-destructive characterisation method probing vibrational modes to infer layer stacking, twist angle, strain and electron–phonon interactions in graphene.

References

1. Twisto-photonics in two-dimensional materials: A comprehensive review. Nanotechnology Reviews (2024).
2. Hetero-site nucleation for growing twisted bilayer graphene with a wide range of twist angles. Nature Communications (2021).
3. Observation of tunable electrical bandgap in large-area twisted bilayer graphene synthesized by chemical vapor deposition. Scientific Reports (2015).
4. Enhanced third-harmonic generation by manipulating the twist angle of bilayer graphene. Light: Science & Applications (2021).
5. In-situ twistable bilayer graphene. Scientific Reports (2022).