A5018158369- Graphene research and applications
- Quantum and electron transport phenomena
- Topological Materials and Phenomena
- 2D Materials and Applications
- Diamond and Carbon-based Materials Research
- Terahertz technology and applications
- Plasmonic and Surface Plasmon Research
- Photonic and Optical Devices
- Semiconductor materials and devices
- MXene and MAX Phase Materials
- Graphene and Nanomaterials Applications
- Semiconductor Quantum Structures and Devices
- Carbon Nanotubes in Composites
- Advancements in Semiconductor Devices and Circuit Design
- Gyrotron and Vacuum Electronics Research
- Photonic Crystals and Applications
- Strong Light-Matter Interactions
- Logic, Reasoning, and Knowledge
- Metamaterials and Metasurfaces Applications
- Quantum Computing Algorithms and Architecture
- Advanced Memory and Neural Computing
- Advancements in Battery Materials
- Fullerene Chemistry and Applications
- Luminescence Properties of Advanced Materials
- Low-power high-performance VLSI design
Nanjing University
2021-2025
Collaborative Innovation Center of Advanced Microstructures
2024
Hankou University
2024
National University of Singapore
2018-2020
University of Leeds
2014-2016
Imperial College London
2016
University of Manchester
2010-2013
Astronomy and Space
2013
Radboud University Nijmegen
2012
University of Exeter
2006-2008
We report a stoichiometric derivative of graphene with fluorine atom attached to each carbon. Raman, optical, structural, micromechanical and transport studies show that the material is qualitatively different from known graphene-based nonstoichiometric derivatives. Fluorographene high-quality insulator (resistivity >10^12 Ohm per square) an optical gap 3 eV. It inherits mechanical strength graphene, exhibiting Young's modulus 100 N/m sustaining strains 15%. inert stable up 400C even in air,...
Devices made from graphene encapsulated in hexagonal boron-nitride exhibit pronounced negative bend resistance and an anomalous Hall effect, which are a direct consequence of room-temperature ballistic transport at micrometer scale for wide range carrier concentrations. The encapsulation makes practically insusceptible to the ambient atmosphere and, simultaneously, allows use boron nitride as ultrathin top gate dielectric.
We investigate the electronic properties of ultrathin hexagonal boron nitride (h-BN) crystalline layers with different conducting materials (graphite, graphene, and gold) on either side barrier layer. The tunnel current depends exponentially number h-BN atomic layers, down to a monolayer thickness. Conductive force microscopy scans across terraces thickness reveal high level uniformity in current. Our results demonstrate that atomically thin acts as defect-free dielectric breakdown field. It...
The nematic phase transition in electronic liquids, driven by Coulomb interactions, represents a new class of strongly correlated ground states. We studied suspended samples bilayer graphene, annealed so that it achieves very high quasiparticle mobilities. Bilayer graphene is truly two-dimensional material with complex chiral spectra and the quality our allowed us to observe strong spectrum reconstructions electron topological transitions can be attributed decrease rotational symmetry. These...
Transport measurements have been a powerful tool for uncovering new electronic phenomena in graphene. We report nonlocal performed the Hall bar geometry with voltage probes far away from classical path of charge flow. observe large response near Dirac point fields as low 0.1T, which persists up to room temperature. The nonlocality is consistent long-range flavor currents induced by lifting spin/valley degeneracy. effect expected contribute strongly all magnetotransport neutrality point.
Capacitance measurements provide a powerful means of probing the density states. The technique has proved particularly successful in studying 2D electron systems, revealing number interesting many-body effects. Here, we use large-area high-quality graphene capacitors to study behavior states this material zero and high magnetic fields. Clear renormalization linear spectrum due electron-electron interactions is observed field. Quantizing fields lead splitting spin- valley-degenerate Landau...
We have performed the first experimental investigation of quantum interference corrections to conductivity a bilayer graphene structure. A negative magnetoresistance--a signature weak localization--is observed at different carrier densities, including electroneutrality region. It is very different, however, from localization in conventional two-dimensional systems. show that it controlled not only by dephasing time, but also elastic processes break effective time-reversal symmetry and...
We report capacitors in which a finite electronic compressibility of graphene dominates the electrostatics, resulting pronounced changes capacitance as function magnetic field and carrier concentration. The measurements have allowed us to accurately map density states D, compare it against theoretical predictions. Landau oscillations D are robust zero level (LL) can easily be seen at room temperature moderate fields. broadening LLs is strongly affected by charge inhomogeneity that leads LL...
The above question is frequently asked by theorists who are interested in graphene as a model system, especially context of relativistic quantum physics. We offer an experimental answer describing electron transport suspended devices with carrier mobilities several 10(6) cm(2) V(-1) s(-1) and the onset Landau quantization occurring fields below 5 mT. observed charge inhomogeneity low ≈10(8) cm(-2), allowing neutral state few carriers per entire micrometer-scale device. Above liquid helium...
We have fabricated graphene devices with a top gate separated from the layer by an air gap-a design which does not decrease mobility of charge carriers under gate. This is used to realize p-n-p structures where conducting properties chiral are studied. The band profile calculated taking into account specifics density states and find resistance p-n junctions expected for carriers. show that ballistic larger than diffusive ones. caused suppressed transmission at angles away normal junction.
Graphene placed on hexagonal-boron nitride (h-BN) experiences a superlattice (Moiré) potential, which leads to strong reconstruction of graphene's electronic spectrum with new Dirac points emerging at sub-eV energies. Here we study the effect such superlattices Raman spectrum. In particular, 2D peak is found be exquisitely sensitive misalignment between graphene and h-BN lattices, probably due presence strain distribution same periodicity Moiré potential. This feature can used identify angle...
We experimentally study the effect of different scattering potentials on $1/f$ noise generated in graphene devices silica substrates. The nominally identical is seen to behave two distinct ways as a function carrier concentration, changing either monotonically or nonmonotonically. attribute this interplay between long- and short-range mechanisms. Water found significantly enhance magnitude change type behavior. By using simple model, we show that water source long-range scattering.
Indium selenide, a post-transition metal chalcogenide, is novel two-dimensional (2D) semiconductor with interesting electronic properties. Its tunable band gap and high electron mobility have already attracted considerable research interest. Here we demonstrate strong quantum confinement manipulation of single electrons in devices made from few-layer crystals InSe using electrostatic gating. We report on gate-controlled dots the Coulomb blockade regime as well one-dimensional quantization...
We report on the use of graphene for room temperature on-chip detection and generation pulsed terahertz (THz) frequency radiation, exploiting fast carrier dynamics light-generated hot carriers, compare our results with conventional low-temperature-grown gallium arsenide (LT-GaAs) photoconductive (PC) switches. Coupling picosecond-duration pulses from a biased PC switch into Goubau line waveguides is also demonstrated. A Drude transport model based transient photoconductance used to describe...
Abstract α-RuCl3 is known for its potential to realize a Kitaev quantum spin liquid by tuning
the competing interactions, such as doping effects. Here, we investigated the doping
effect of α-RuCl3/graphene heterostructures and observed G peak splitting related
to different spins, revealed Raman spectroscopy. The deliberate disruption the
heterostructure led transition from double single peak, underscoring
the significance interface quality. This...
<title>Abstract</title> For several decades, research has centered on electronic systems where an electron’s kinetic energy rivals its interaction energy. Although many have been proposed, none enable continuous tuning of key parameters, such as doping or work function. By contrast, graphene permits precise carrier density control via gating, but sample inhomogeneities hinder access to the low-density regime electron-electron interactions dominate. Improving graphene’s mobility remains...
Terahertz frequency time-domain spectroscopy employing free-space radiation has frequently been used to probe the elementary excitations of low-dimensional systems. The diffraction limit, however, prevents its use for in-plane study individual laterally-defined nanostructures. Here, we demonstrate a planar terahertz plasmonic circuit in which photoconductive material is monolithically integrated with two-dimensional electron system. Plasmons broad spectral range (up ~ 400 GHz) are excited by...
We demonstrate the feasibility of using graphene as a conductive electrode for generation and detection surface acoustic waves at 100 s MHz on lithium niobate substrate. The interdigitated transducers (IDTs) show sensitivity to doping temperature, characteristics IDTs are discussed in context lossy transmission line model.
Abstract A stoichiometric derivative of graphene with a fluorine atom attached to each carbon is reported. Raman, optical, structural, micromechanical, and transport studies show that the material qualitatively different from known graphene‐based nonstoichiometric derivatives. Fluorographene high‐quality insulator (resistivity >10 12 Ω ) an optical gap 3 eV. It inherits mechanical strength graphene, exhibiting Young’s modulus 100 N m −1 sustaining strains 15%. inert stable up 400 °C even...