Cross-sectional imaging of individual layers and buried interfaces of graphene-based heterostructures and superlattices

Abstract

By stacking various two-dimensional (2D) atomic crystals [1] on top of each other, it is possible to create multilayer heterostructures and devices with designed electronic properties [2-5]. However, various adsorbates become trapped between layers during their assembly, and this not only affects the resulting quality but also prevents the formation of a true artificial layered crystal upheld by van der Waals interaction, creating instead a laminate glued together by contamination. Transmission electron microscopy (TEM) has shown that graphene and boron nitride monolayers, the two best characterized 2D crystals, are densely covered with hydrocarbons (even after thermal annealing in high vacuum) and exhibit only small clean patches suitable for atomic resolution imaging [6-10]. This observation seems detrimental for any realistic prospect of creating van der Waals materials and heterostructures with atomically sharp interfaces. Here we employ cross sectional TEM to take a side view of several graphene-boron nitride heterostructures. We find that the trapped hydrocarbons segregate into isolated pockets, leaving the interfaces atomically clean. Moreover, we observe a clear correlation between interface roughness and the electronic quality of encapsulated graphene. This work proves the concept of heterostructures assembled with atomic layer precision and provides their first TEM images.

References in corpus (15)

• The electronic properties of graphene
• Two Dimensional Atomic Crystals
• Boron nitride substrates for high-quality graphene electronics
• The structure of suspended graphene sheets
• Field-effect tunneling transistor based on vertical graphene heterostructures
• Micrometer-scale ballistic transport in encapsulated graphene at room temperature
• Emergence of Superlattice Dirac Points in Graphene on Hexagonal Boron Nitride
• Atomically thin boron nitride: a tunnelling barrier for graphene devices
• Tunable metal-insulator transition in double-layer graphene heterostructures
• Electron scattering on microscopic corrugations in graphene
• Raman spectroscopy of graphene and bilayer under biaxial strain: bubbles and balloons
• Room-Temperature Superfluidity in Graphene Bilayers
• Graphene bubbles with controllable curvature
• BN/Graphene/BN Transistors for RF Applications
• Tunneling Spectroscopy of Graphene-Boron Nitride Heterostructures

Cited by in corpus (175)

• Van der Waals heterostructures
• 2D materials and van der Waals heterostructures
• Atomically thin p-n junctions with van der Waals heterointerfaces
• Vertical Field Effect Transistor based on Graphene-WS2 Heterostructures for flexible and transparent electronics
• Light-emitting diodes by bandstructure engineering in van der Waals heterostructures
• Cloning of Dirac fermions in graphene superlattices
• Strong interlayer coupling in van der Waals heterostructures built from single-layer chalcogenides
• Commensurate-incommensurate transition for graphene on hexagonal boron nitride
• Strong Oxidation Resistance of Atomically Thin Boron Nitride Nanosheets
• Detecting Topological Currents in Graphene Superlattices
• Molecular transport through capillaries made with atomic-scale precision
• The hot pick-up technique for batch assembly of van der Waals heterostructures
• Negative local resistance caused by viscous electron backflow in graphene
• Size effect in ion transport through angstrom-scale slits
• Resonant tunnelling and negative differential conductance in graphene transistors
• Recent progress in the assembly of nanodevices and van der Waals heterostructures by deterministic placement of 2D materials
• Twist-controlled resonant tunnelling in graphene-boron nitride-graphene heterostructures
• Electronic Properties of Graphene Encapsulated with Different Two-Dimensional Atomic Crystals
• Cleaning Interfaces in Layered Materials Heterostructures
• Quality heterostructures from two dimensional crystals unstable in air by their assembly in inert atmosphere
• Atomically Thin Resonant Tunnel Diodes built from Synthetic van der Waals Heterostructures
• Strong interface-induced spin-orbit coupling in graphene on WS2
• Light Generation and Harvesting in a Van der Waals Heterostructure
• Broadband Photovoltaic Detectors based on an Atomically Thin Heterostructure
• Fast pick up technique for high quality heterostructures of bilayer graphene and hexagonal boron nitride
• Graphene bubbles on a substrate : Universal shape and van der Waals pressure
• Limits on gas impermeability of graphene
• Charge-polarized interfacial superlattices in marginally twisted hexagonal boron nitride
• Interaction phenomena in graphene seen through quantum capacitance
• WSe2 light-emitting tunneling transistors with enhanced brightness at room temperature
• Gate Tunable Quantum Oscillations in Air-Stable and High Mobility Few-Layer Phosphorene Heterostructures
• Atomically sharp interface enabled ultrahigh-speed, nonvolatile memory devices
• Imaging strain-localized exciton states in nanoscale bubbles in monolayer WSe2 at room temperature
• Ballistic molecular transport through two-dimensional channels
• Quasiparticle GW calculations for solids, molecules and 2D materials
• Minimizing Residues and Strain in 2D Materials Transferred from PDMS
• Direct growth of single- and few-layer MoS2 on h-BN with preferred relative rotation angles
• Van der Waals pressure and its effect on trapped interlayer molecules
• Interlayer exciton dynamics in a dichalcogenide monolayer heterostructure
• Heterostructures produced from nanosheet-based inks
• The pristine atomic structure of MoS2 monolayer protected from electron radiation damage by graphene
• Strained bubbles in van der Waals heterostructures as local emitters of photoluminescence with adjustable wavelength
• Dielectric Screening in Atomically Thin Boron Nitride Nanosheets
• Band offset and negative compressibility in graphene-MoS2 heterostructures
• The Effect of Preparation Conditions on Raman and Photoluminescence of Monolayer WS2
• Interface coupling in twisted multilayer graphene by resonant Raman spectroscopy of layer breathing modes
• Proximity effect in graphene-topological insulator heterostructures
• Doping Mechanisms in Graphene-MoS2 Hybrids
• Nanobubble induced formation of quantum emitters in monolayer semiconductors
• Ultra-clean assembly of van der Waals heterostructures
• High-T_c superconductivity in ultrathin Bi_2Sr_2CaCu_2O_8+x down to halfunit-cell thickness by protection with graphene
• Engineering of Neutral Excitons and Exciton Complexes in Transition Metal Dichalcogenide Monolayers through External Dielectric Screening
• Indirect to direct gap crossover in two-dimensional InSe revealed by ARPES
• Breakdown of the interlayer coherence in twisted bilayer graphene
• Unraveling the 3D atomic structure of a suspended graphene/hBN van der Waals heterostructure
• Graphene on Hexagonal Boron Nitride
• Ferromagnetic two-dimensional crystals: Single layers of K2CuF4
• Charge versus energy transfer in atomically-thin graphene-transition metal dichalcogenide van der Waals heterostructures
• Observing imperfection in atomic interfaces for van der Waals heterostructures
• Ion exchange in atomically thin clays and micas
• A Two-dimensional Dirac fermion microscope
• Electronic Hybridization of Large-Area Stacked Graphene Films
• Hexagonal Boron Nitride (hBN) as a Low-loss Dielectric for Superconducting Quantum Circuits and Qubits
• Band gap renormalization and work function tuning in MoSe2/hBN/Ru(0001) heterostructures
• Moire superlattice effects in graphene/boron-nitride van der Waals heterostructures
• Large tunable valley splitting in edge-free graphene quantum dots on boron nitride
• Reliable postprocessing improvement of van der Waals heterostructures
• Electronic, optical and transport properties of van der Waals Transition-metal Dichalcogenides Heterostructures: A First-principle Study
• Quantum-Matter Heterostructures
• Electrical spin injection, transport, and detection in graphene-hexagonal boron nitride van der Waals heterostructures: progress and perspectives
• Electronic transport in graphene-based heterostructures
• The Electronic Thickness of Graphene
• Towards Air Stability of Ultra-Thin GaSe Devices: Avoiding Environmental and Laser-Induced Degradation by Encapsulation
• Giant Edelstein effect in Topological-Insulator--Graphene heterostructures
• Towards Exotic Layered Materials: 2D Cuprous Iodide
• Long Phonon Mean Free Paths Observed in Cross-plane Thermal-Conductivity Measurements of Exfoliated Hexagonal Boron Nitride
• Universal classification of twisted, strained and sheared graphene moiré superlattices
• High-quality electrical transport using scalable CVD graphene
• Exploring Two-Dimensional Empty Space
• Nanosecond spin relaxation times in single layer graphene spin valves with hexagonal boron nitride tunnel barriers
• All-Dry Transfer of Graphene Film by Van der Waals Interactions
• Van der Waals interaction affects wrinkle formation in two-dimensional materials
• Rapid and catalyst-free CVD growth of graphene on hBN
• Pinpoint pick-up and bubble-free assembly of 2D materials using PDMS/PMMA polymers with lens shapes
• Nanoscale modification of WS${}_2$ trion emission by its local electromagnetic environment
• Efficient spin injection into graphene through a tunnel barrier: overcoming the spin conductance mismatch
• Interlayer Coupling in Two-Dimensional Semiconductor Materials
• Mechanical and liquid phase exfoliation of cylindrite: a natural van der Waals superlattice with intrinsic magnetic interactions
• Fabrication of angstrom-scale two-dimensional channels for mass transport
• Emergence of Tertiary Dirac Points in Graphene Moiré Superlattices
• Dark-exciton driven energy funneling into dielectric inhomogeneities in two-dimensional semiconductors
• Engineering Topological Surface States and Giant Rashba Spin Splitting in BiTeI/Bi${}_2$Te${}_3$ Heterostructures
• Tailoring the dielectric screening in WS${}_2$-graphene heterostructures
• A system for the deterministic transfer of 2D materials under inert environmental conditions
• Chiral superfluid states in hybrid graphene heterostructures
• Influence of the Constant Electric Field on the Mutual Rectification of the Electromagnetic Waves in Graphene Superlattice
• Phase slip lines in superconducting few-layer NbSe${}_2$ crystals
• Flattening van der Waals heterostructure interfaces by local thermal treatment
• Light-matter interaction in van der Waals heterostructures
• Ground state of graphene heterostructures in the presence of random charged impurities
• Substrate influence on transition metal dichalcogenide monolayer exciton absorption linewidth broadening
• Highly Accurate, Reliable and Non-Contaminating Two-Dimensional Material Transfer System
• Nanoscale electrostatic control in ultra clean van der Waals heterostructures by local anodic oxidation of graphite gates
• Proximity screening greatly enhances electronic quality of graphene
• Convergent beam electron holography for analysis of van der Waals heterostructures
• Strain and Water Effects on the Electronic Structure and Chemical Activity of In-Plane Graphene/Silicene Heterostructure
• Graphene vertical hot-electron terahertz detectors
• Theory of quantum entanglement and the structure of two-mode squeezed antiferromagnetic magnon vacuum
• Fabrication-induced even-odd discrepancy of magnetotransport in few-layer MnBi${}_2$Te${}_4$
• Liquid metal intercalation of epitaxial graphene: large-area gallenene layer fabrication through gallium self-propagation at ambient conditions
• Twist-controlled Resonant Tunnelling between Monolayer and Bilayer Graphene
• Topological Zero-Line Modes in Folded Bilayer Graphene
• Aligned Stacking of Nanopatterned 2D materials -- Towards 3D printing at atomic resolution
• Moiré superlattice effects and band structure evolution in near-30-degree twisted bilayer graphene
• Thickness dependent interlayer transport in vertical MoS2 Josephson junctions
• Probing the Shape of a Graphene Nanobubble
• Structural, electronic, and optical properties of periodic graphene/h-BN van der Waals heterostructures
• Dirac Fermion Cloning, Moir$\acute{\mathbf{e}}$ Flat Bands and Magic Lattice Constants in Epitaxial Monolayer Graphene
• Alternating currents and shear waves in viscous electronics
• Optical spectroscopy of interlayer coupling in artificially stacked MoS2 layers
• Atomic Resolution Imaging of CrBr${}_3$ using Adhesion-Enhanced Grids
• Extraordinary Photostability and Davydov Splitting in BN-Sandwiched Single-Layer Tetracene Molecular Crystals
• Magnetotransport in single layer graphene in a large parallel magnetic field
• Ag and Au Atoms Intercalated in Bilayer Heterostructures of Transition Metal Dichalcogenides and Graphene
• Infrared absorption of closely-aligned heterostructures of monolayer and bilayer graphene with hexagonal boron nitride
• Multiple negative differential conductance regions and inelastic phonon assisted tunneling in graphene-hBN-graphene structures
• A flux tunable superconducting quantum circuit based on Weyl semimetal MoTe2
• Out-of-plane corrugations in graphene based van der Waals heterostructures
• Effect of a spin-active interface on proximity-induced superconductivity in topological insulators
• Ultrafast nano-imaging of dark excitons
• Spin and charge transport in graphene-based spin transport devices with Co/MgO spin injection and spin detection electrodes
• Distance dependence of the energy transfer mechanism in WS${}_2$-graphene heterostructures
• Chemical vapor deposition growth of bilayer graphene in between molybdenum disulfide sheets
• Exciton-Sensitized Second-Harmonic Generation in 2D Heterostructures
• Hydrocarbon Contamination in Angstrom-scale Channels
• Strongly Absorbing Nanoscale Infrared Domains within Graphene Bubbles
• Convergent beam electron diffraction of multilayer van der Waals structures
• Carbon-related Bilayers: Nanoscale Building Blocks for Self-Assembly Nanomanufacturing
• Electronic Transport and Thermopower in 2D and 3D Heterostructures--A Theory Perspective
• Highly Integrated Organic-Inorganic Hybrid Architectures by Non-Covalent Exfoliation of Graphite and Assembly with Zinc Oxide Nanoparticles
• Infrared spectroscopy of hole doped ABA-stacked trilayer graphene
• Direct visualization of defect-controlled diffusion in van der Waals gaps
• Band structures and ${\mathbb{Z}}_2$ invariants of two-dimensional transition metal dichalcogenide monolayers from fully-relativistic Dirac-Kohn-Sham theory using Gaussian-type orbitals
• Anisotropic strain effects in small-twist-angle graphene on graphite
• Designing Fe Nanostructures at Graphene/h-BN Interfaces
• The effect of anomalous elasticity on the bubbles in van der Waals heterostructures
• Revealing the topological phase diagram of ZrTe${}_5$ using the complex strain fields of microbubbles
• Nano-Raman Spectroscopy Analysis of Nanoprotuberances in MoSe2
• Chiral properties of graphene h-BN hybrid systems
• Incoherent phonon transport dominates heat conduction across van der Waals superlattices
• Holographic reconstruction of the interlayer distance of bilayer two-dimensional crystal samples from their convergent beam electron diffraction patterns
• Multi-terminal electrical transport measurements of molybdenum disulphide using van der Waals heterostructure device platform
• Negative differential resistance in Van der Waals heterostructures due to moiré-induced spectral reconstruction
• Quantification of 2D Interfaces: Quality of heterostructures, and what is inside a nanobubble
• Atomically-precise synthesis and simultaneous integration of 2D transition metal dichalcogenides enabled by nano-confinement
• Strain-engineered wrinkles on graphene using polymeric actuators
• Electronic structure of 2D van der Waals crystals and heterostructures investigated by spatially- and angle-resolved photoemission
• Integration of graphene-based superconducting quantum circuits in 3D cavity
• Tuning of Interlayer Coupling in Large-Area Graphene/WSe2 van der Waals Heterostructure via Ion Irradiation: Optical Evidences and Photonic Applications
• Interface engineering of van der Waals heterostructures towards energy-efficient quantum devices operating at high temperatures
• Potentials of individual atoms by convergent beam electron diffraction
• Identifying atomically thin crystals with diffusively reflected light
• Holographic convergent electron beam diffraction (CBED) imaging of two-dimensional crystals
• Assembly of High-Performance van der Waals Devices Using Commercial Polyvinyl Chloride Films
• Moiré spintronics: Emergent phenomena, material realization and machine learning accelerating discovery
• Enhancement of the WS${}_2$ A${}_{1\text{g}}$ Raman Mode in MoS${}_2$/WS${}_2$ Heterostructures
• Substrate pre-sputtering for layer-by-layer van der Waals epitaxy of 2D materials
• Plasmon-Enhanced Interface Charge Transfer Exciton of 2D In-Plane Lateral and van Der Waals MoS${}_2$/WS${}_2$ Heterostructures
• Anomalous elastic buckling of hexagonal layered crystalline materials in the absence of structure slenderness
• Optical Imaging of Chemically and Geometrically Controlled Interfacial Diffusion and Redox in 2D van der Waals Space
• Untangling 3D atomic reconstruction in twisted bilayer 2D crystals via dark field transmission electron microscopy
• Ubiquitous Antiparallel Domains in 2D Hexagonal Boron Nitride Uncovered by Interferometric Nonlinear Optical Imaging
• How high is a MoSe${}_2$ monolayer?
• Study of gold and bismuth electrical contacts to a MoS${}_2$ monolayer
• Low-dimensional platforms for single photon detection