A new route to graphene layers by selective laser ablation
TL;DR: For the 2D regime of graphite (up to N≈7), the dominant flexural mode specific heat (due to its N-1 dependence) gives rise to a strong layer number-dependence on the pulsed laser ablation threshold energy density, while for 3D regime (N>>7) the energy density windows exist between the minimum energy densities that are required for ablating single, bi, or more layers of graphene, allowing layer number selectivity as discussed by the authors.
Abstract: Selectively creating regions of spatially varying thickness may enable the utilization of the electronic properties of N-layer (N=1 or more) graphene and other similar layered materials (e.g., topological insulators or layered superconductors) for novel devices and functionalities on a single chip. The ablation threshold energy density increases dramatically for decreasing layer numbers of graphene originating from the dimensional crossover of the specific heat. For the 2D regime of graphite (up to N≈7) the dominant flexural mode specific heat (due to its N-1 dependence) gives rise to a strong layer number-dependence on the pulsed laser ablation threshold energy density, while for 3D regime (N>>7) the ablation threshold saturates due to dominant acoustic mode specific heat. As a result, several energy density windows exist between the minimum energy densities that are required for ablating single, bi, or more layers of graphene, allowing layer number selectivity.
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TL;DR: This work reviews recent progress in graphene research and in the development of production methods, and critically analyse the feasibility of various graphene applications.
Abstract: Recent years have witnessed many breakthroughs in research on graphene (the first two-dimensional atomic crystal) as well as a significant advance in the mass production of this material. This one-atom-thick fabric of carbon uniquely combines extreme mechanical strength, exceptionally high electronic and thermal conductivities, impermeability to gases, as well as many other supreme properties, all of which make it highly attractive for numerous applications. Here we review recent progress in graphene research and in the development of production methods, and critically analyse the feasibility of various graphene applications.
7,987 citations
University of Cambridge1, Istituto Italiano di Tecnologia2, Lancaster University3, University of Manchester4, Catalan Institution for Research and Advanced Studies5, Technical University of Denmark6, Nokia7, fondazione bruno kessler8, University of Trento9, Queen Mary University of London10, Technische Universität München11, Polytechnic University of Milan12, Centre national de la recherche scientifique13, University of Trieste14, University of Ioannina15, University of Geneva16, Trinity College, Dublin17, Texas Instruments18, University of Paris19, Spanish National Research Council20, Leiden University21, Delft University of Technology22, University of Patras23, École Normale Supérieure24, Radboud University Nijmegen25, Nest Labs26, Airbus UK27, Seoul National University28, Yonsei University29, University of Oxford30, Chalmers University of Technology31, University of Groningen32, STMicroelectronics33, Chemnitz University of Technology34, Max Planck Society35, Aalto University36
TL;DR: An overview of the key aspects of graphene and related materials, ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries are provided.
Abstract: We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.
2,560 citations
TL;DR: Graphene is at the center of an ever growing research effort due to its unique properties, interesting for both fundamental science and applications as mentioned in this paper, and a key requirement for applications is the development of industrial-scale, reliable, inexpensive production processes.
968 citations
TL;DR: In this paper, the authors present an overview of 2D crystals based ultrafast photonics, from solution processing of the raw bulk materials, the fabrication of saturable absorbers, to their applications in ultrafast lasers.
Abstract: Graphene and other two-dimensional (2d) crystals are promising materials for photonic and optoelectronic applications. A key requirement for these applications is the development of industrial-scale, reliable, inexpensive production processes, while providing a balance between ease of fabrication and final material quality with on-demand properties. Solution-processing offers a simple and cost-effective pathway to fabricate various 2d crystal based photonic devices, presenting huge integration flexibility compared to conventional methods. Here we present an overview of graphene and other 2d crystals based ultrafast photonics, from solution processing of the raw bulk materials, the fabrication of saturable absorbers, to their applications in ultrafast lasers.
183 citations
TL;DR: In this article, a review of laser-induced graphene oxide reduction and modification is presented, focusing on the main reduction ways and the laser parameters used in the literature, and a discussion of possible reduction and modifications mechanisms is also presented.
Abstract: A dramatic rise in research interest in laser-induced graphene oxide (GO) reduction and modification requires an overview of the most recent works on this subject. Typical methods for the recognition and confirmation of modified graphene and its derivatives, such as Raman, Fourier-transform infra-red (FTIR), X-ray photoelectron (XP), and ultraviolet-visible (UV–vis) spectroscopies, are introduced briefly in this review. A major part of the survey is devoted to the main modification ways and the laser parameters used in the literature. A discussion of possible reduction and modification mechanisms is also presented. Recent applications, especially in the biomedical field such as cell therapy treatment, as well as significant results of GO modification, are discussed in detail. Finally, perspectives for the application of laser-induced GO modifications in passive THz photonics and biomedicine are briefly addressed.
132 citations
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TL;DR: Monocrystalline graphitic films are found to be a two-dimensional semimetal with a tiny overlap between valence and conductance bands and they exhibit a strong ambipolar electric field effect.
Abstract: We describe monocrystalline graphitic films, which are a few atoms thick but are nonetheless stable under ambient conditions, metallic, and of remarkably high quality. The films are found to be a two-dimensional semimetal with a tiny overlap between valence and conductance bands, and they exhibit a strong ambipolar electric field effect such that electrons and holes in concentrations up to 10 13 per square centimeter and with room-temperature mobilities of ∼10,000 square centimeters per volt-second can be induced by applying gate voltage.
55,532 citations
TL;DR: In this paper, the basic theoretical aspects of graphene, a one-atom-thick allotrope of carbon, with unusual two-dimensional Dirac-like electronic excitations, are discussed.
Abstract: This article reviews the basic theoretical aspects of graphene, a one-atom-thick allotrope of carbon, with unusual two-dimensional Dirac-like electronic excitations. The Dirac electrons can be controlled by application of external electric and magnetic fields, or by altering sample geometry and/or topology. The Dirac electrons behave in unusual ways in tunneling, confinement, and the integer quantum Hall effect. The electronic properties of graphene stacks are discussed and vary with stacking order and number of layers. Edge (surface) states in graphene depend on the edge termination (zigzag or armchair) and affect the physical properties of nanoribbons. Different types of disorder modify the Dirac equation leading to unusual spectroscopic and transport properties. The effects of electron-electron and electron-phonon interactions in single layer and multilayer graphene are also presented.
20,824 citations
TL;DR: This work shows that graphene's electronic structure is captured in its Raman spectrum that clearly evolves with the number of layers, and allows unambiguous, high-throughput, nondestructive identification of graphene layers, which is critically lacking in this emerging research area.
Abstract: Graphene is the two-dimensional building block for carbon allotropes of every other dimensionality We show that its electronic structure is captured in its Raman spectrum that clearly evolves with the number of layers The D peak second order changes in shape, width, and position for an increasing number of layers, reflecting the change in the electron bands via a double resonant Raman process The G peak slightly down-shifts This allows unambiguous, high-throughput, nondestructive identification of graphene layers, which is critically lacking in this emerging research area
13,474 citations
TL;DR: This review analyzes recent trends in graphene research and applications, and attempts to identify future directions in which the field is likely to develop.
Abstract: Graphene is a wonder material with many superlatives to its name. It is the thinnest known material in the universe and the strongest ever measured. Its charge carriers exhibit giant intrinsic mobility, have zero effective mass, and can travel for micrometers without scattering at room temperature. Graphene can sustain current densities six orders of magnitude higher than that of copper, shows record thermal conductivity and stiffness, is impermeable to gases, and reconciles such conflicting qualities as brittleness and ductility. Electron transport in graphene is described by a Dirac-like equation, which allows the investigation of relativistic quantum phenomena in a benchtop experiment. This review analyzes recent trends in graphene research and applications, and attempts to identify future directions in which the field is likely to develop.
12,117 citations
TL;DR: Measurements show that mobilities higher than 200 000 cm2/V s are achievable, if extrinsic disorder is eliminated and a sharp (thresholdlike) increase in resistivity observed above approximately 200 K is unexpected but can qualitatively be understood within a model of a rippled graphene sheet in which scattering occurs on intraripple flexural phonons.
Abstract: We have studied temperature dependences of electron transport in graphene and its bilayer and found extremely low electron-phonon scattering rates that set the fundamental limit on possible charge carrier mobilities at room temperature. Our measurements show that mobilities higher than 200 000 cm2/V s are achievable, if extrinsic disorder is eliminated. A sharp (thresholdlike) increase in resistivity observed above approximately 200 K is unexpected but can qualitatively be understood within a model of a rippled graphene sheet in which scattering occurs on intraripple flexural phonons.
3,100 citations