A5091528896- Graphene research and applications
- 2D Materials and Applications
- Quantum and electron transport phenomena
- Topological Materials and Phenomena
- Diamond and Carbon-based Materials Research
- Surface and Thin Film Phenomena
- MXene and MAX Phase Materials
- Chalcogenide Semiconductor Thin Films
- Electron and X-Ray Spectroscopy Techniques
- Advanced Electron Microscopy Techniques and Applications
- Nanopore and Nanochannel Transport Studies
- Advanced Memory and Neural Computing
- Electronic and Structural Properties of Oxides
- Carbon Nanotubes in Composites
- Semiconductor materials and devices
- Plasmonic and Surface Plasmon Research
- Perovskite Materials and Applications
- Solid-state spectroscopy and crystallography
- Thermal properties of materials
- Spectroscopy and Quantum Chemical Studies
- Graphene and Nanomaterials Applications
- Advancements in Battery Materials
- Boron and Carbon Nanomaterials Research
- Nanowire Synthesis and Applications
- Quantum Dots Synthesis And Properties
Henry Royce Institute
2016-2024
University of Manchester
2015-2024
Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine
2021
Astronomy and Space
2012-2015
University of Exeter
2007-2009
Instituto de Ciencia de Materiales de Madrid
2008
Nikolaev Institute of Inorganic Chemistry
2005
We report a bipolar field effect tunneling transistor that exploits to advantage the low density of states in graphene and its one atomic layer thickness. Our proof-of-concept devices are heterostructures with atomically thin boron nitride acting as tunnel barrier. They exhibit room temperature switching ratios ~50, value can be enhanced further by optimizing device structure. These have potential for high frequency operation large scale integration.
The isolation of various two-dimensional (2D) materials, and the possibility to combine them in vertical stacks, has created a new paradigm materials science: heterostructures based on 2D crystals. Such concept already proven fruitful for number electronic applications area ultrathin flexible devices. Here, we expand range such structures photoactive ones by using semiconducting transition metal dichalcogenides (TMDCs)/graphene stacks. Van Hove singularities density states TMDC guarantees...
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 identification of single- and few-layer boron nitride is described. Its optical contrast much smaller than that graphene, but even monolayers are discernable by optimizing viewing conditions. number layers in thicker crystals can be counted exploiting an integer-step increase the Raman intensity contrast.
Topological materials may exhibit Hall-like currents flowing transversely to the applied electric field even in absence of a magnetic field. In graphene superlattices, which have broken inversion symmetry, topological originating from graphene's two valleys are predicted flow opposite directions and combine produce long-range charge neutral flow. We observed this effect as nonlocal voltage at zero narrow energy range near Dirac points distances large several micrometers away nominal current...
The chemical stability of graphene and other free-standing two-dimensional crystals means that they can be stacked in different combinations to produce a new class functional materials, designed for specific device applications. Here we report resonant tunnelling Dirac fermions through boron nitride barrier, few atomic layers thick, sandwiched between two electrodes. peak the characteristics occurs when electronic spectra electrodes are aligned. resulting negative differential conductance...
We show that the manifestation of quantum interference in graphene is very different from conventional two-dimensional systems. Because chiral nature charge carriers, it not only sensitive to inelastic, phase-breaking scattering, but also a number elastic scattering processes. study weak localization samples and at carrier densities, including Dirac region, find characteristic rates determine it. how shape quality flakes affect values inelastic discuss their physical origin.
Many layered materials can be cleaved down to individual atomic planes, similar graphene, but only a small minority of them are stable under ambient conditions. The rest react and decompose in air, which has severely hindered their investigation potential applications. Here we introduce remedial approach based on cleavage, transfer, alignment, encapsulation air-sensitive crystals, all inside controlled inert atmosphere. To illustrate the technology, choose two archetypal two-dimensional...
We show that quantum interference in graphene can result antilocalization of charge carriers---an increase the conductance, which is detected by a negative magnetoconductance. demonstrate depending on experimental conditions one observe either weak localization or carriers graphene. A transition from to occurs when carrier density decreased and temperature increased. survive at high temperatures, up $T\ensuremath{\sim}200\text{ }\text{ }\mathrm{K}$, due electron-phonon scattering.
The temperature dependence of the mobility in suspended graphene samples is investigated. In clean samples, flexural phonons become leading scattering mechanism at $T \gtrsim 10\,\,$K, and resistivity increases quadratically with $T$. Flexural limit intrinsic down to a few $\text{m}^2/\text{Vs}$ room Their effect can be eliminated by applying strain or placing on substrate.
Hexagonal boron nitride is the only substrate that has so far allowed graphene devices exhibiting micron-scale ballistic transport. Can other atomically flat crystals be used as substrates for making quality heterostructures? Here we report on our search alternative substrates. The fabricated by encapsulating with molybdenum or tungsten disulphides and hBN are found to exhibit consistently high carrier mobilities of about 60,000 cm$^{2}$V$^{-1}$s$^{-1}$. In contrast, encapsulation layered...