Graphene

Graphene
AlexanderAlUS · CC BY-SA 3.0 · source
Category	Allotrope
Appearance	Metallic lustre
Discovered	2004
Discoverers	Andre Geim, Konstantin Novoselov

Graphene Graphene is a two-dimensional allotrope of carbon consisting of a single layer of sp2-bonded carbon atoms arranged in a hexagonal lattice. It has attracted attention across Nobel Prize in Physics, University of Manchester, Royal Society, European Research Council and National Science Foundation-funded programs for its exceptional electrical, mechanical and thermal properties. Research on graphene involves collaborations among institutions such as Massachusetts Institute of Technology, University of Cambridge, Max Planck Society, Chinese Academy of Sciences and Riken.

Introduction

Graphene emerged as a focus after experiments at University of Manchester led by Andre Geim and Konstantin Novoselov, whose work was recognized by the Nobel Prize in Physics. Early investigations intersected with developments at Bell Labs, IBM Research, Rice University, Columbia University and KAIST. International efforts include projects funded by the European Commission, Japan Science and Technology Agency, National Natural Science Foundation of China and DARPA. Conferences and journals such as Materials Research Society, American Chemical Society, Nature Nanotechnology and Science disseminate findings.

Structure and properties

Graphene's honeycomb lattice yields a linear electronic dispersion at the K and K' points of the Brillouin zone, producing massless Dirac fermions described by concepts tested in contexts like Dirac equation, Quantum Hall effect, Fractional Quantum Hall effect, Band theory of solids and Topological insulator studies. Mechanical properties rival those measured for materials in Tensile testing at facilities like National Institute of Standards and Technology; graphene exhibits high Young's modulus and fracture strength comparable to values reported for Kevlar and Carbon nanotube-reinforced composites. Thermal conductivity values approach those found in Diamond; electronic mobility has been benchmarked against materials used by Intel and Samsung in semiconductor research. Optical absorption per layer links to constants studied in Optical conductivity and Fine-structure constant research. Defects such as vacancies, grain boundaries and functional groups influence properties, motivating studies in Scanning tunneling microscopy, Transmission electron microscopy and Raman spectroscopy contexts.

Synthesis and production methods

Mechanical exfoliation using tape, developed in the experiments associated with Andre Geim and Konstantin Novoselov, produces high-quality flakes used by groups at Columbia University and University of Manchester. Chemical vapor deposition (CVD) on substrates such as copper or Nickel is employed by industrial partners including Samsung and LG for wafer-scale films. Epitaxial growth on Silicon carbide has been pursued by teams at IBM Research and Epitronics. Liquid-phase exfoliation and reduction of graphene oxide trace to methods refined by laboratories at University of California, Berkeley, Universidad Autónoma de Madrid and Drexel University. Chemical routes involve reagents and processes studied in Royal Society of Chemistry-published protocols; roll-to-roll manufacturing efforts intersect with pilot plants at companies linked to European Commission innovation initiatives. Quality control across methods is guided by standards bodies such as International Organization for Standardization efforts focused on nanomaterials.

Characterization techniques

Microscopy modalities used include Scanning tunneling microscopy and Transmission electron microscopy as applied at centers like EMBL and Lawrence Berkeley National Laboratory. Spectroscopy techniques—Raman spectroscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy—are routine in groups at Stanford University, ETH Zurich and National Institute for Materials Science. Electrical transport measurements referencing Hall effect and Four-point probe methods are standard in labs at MIT and Tsinghua University. Thermal characterization leverages techniques developed at Oak Ridge National Laboratory and NIST. Surface analysis and chemical mapping use Atomic force microscopy variants and instruments from manufacturers aligned with research at CNRS and Fraunhofer Society.

Applications

Proposed and demonstrated applications span many sectors. In electronics, graphene has been investigated for use in field-effect transistors and interconnects by companies like IBM and Intel and in research at MIT and Samsung. In composites, graphene additives have been studied alongside Kevlar and Carbon fiber materials by aerospace groups at Airbus and Boeing. Energy applications include electrodes for lithium-ion battery development at Tesla, Panasonic collaborations and University of Oxford research on supercapacitors linked to Maxwell Technologies-style devices. Sensor technologies leverage graphene's surface sensitivity in projects at Imperial College London and University of California, Berkeley for biosensors and gas detection aligned with FDA-regulated medical device pathways. Membrane and filtration efforts interact with initiatives at MIT and National University of Singapore for water desalination and gas separation. Photonics and optoelectronics research at EPFL and University of Cambridge explore modulators, photodetectors and transparent conductors relevant to displays by Sony and LG.

Environmental, health and safety considerations

Studies by regulatory and research bodies such as Environmental Protection Agency, European Chemicals Agency, National Institute for Occupational Safety and Health and Health and Safety Executive examine exposure risks, inhalation toxicity and environmental fate of graphene-related materials. Toxicology investigations have been conducted at Imperial College London, Karolinska Institute and Johns Hopkins University assessing cytotoxicity, pulmonary effects and ecotoxicology in contexts similar to studies of Carbon nanotubes and Fullerenes. Life-cycle assessment work involves teams at University of Cambridge, TU Delft and Yale University analyzing energy inputs, cradle-to-grave impacts and recycling parallels with Silicon-based electronics. Standards and safe-handling guidance are influenced by reports from ISO and national agencies mapping onto occupational frameworks used in industry.

Research directions and challenges

Current research priorities include bandgap engineering via heterostructures with Hexagonal boron nitride, integration with Transition metal dichalcogenides, scalable high-quality synthesis for fabs pursued by TSMC and GlobalFoundries, and reliable functionalization strategies studied at University of Illinois Urbana-Champaign and Columbia University. Challenges involve reproducibility, wafer-scale uniformity, defect control, and establishing supply chains akin to those for Silicon and Graphite producers. Fundamental studies connect to developments in Quantum computing, Spintronics, Plasmonics, and 2D materials research communities supported by agencies like DARPA and European Research Council. Interdisciplinary efforts span collaborations among universities, national labs and industry to address commercialization pathways and regulatory frameworks exemplified by precedents at NIH and European Commission.

Category:Carbon allotropes