What is Graphene: Definition and 208 Discussions

Graphene () is an allotrope of carbon consisting of a single layer of atoms arranged in a two-dimensional honeycomb lattice. The name is a portmanteau of "graphite" and the suffix -ene, reflecting the fact that the graphite allotrope of carbon consists of stacked graphene layers.Each atom in a graphene sheet is connected to its three nearest neighbors by a σ-bond, and contributes one electron to a conduction band that extends over the whole sheet. This is the same type of bonding seen in carbon nanotubes and polycyclic aromatic hydrocarbons, and (partially) in fullerenes and glassy carbon. These conduction bands make graphene a semimetal with unusual electronic properties that are best described by theories for massless relativistic particles. Charge carriers in graphene show linear, rather than quadratic, dependence of energy on momentum, and field-effect transistors with graphene can be made that show bipolar conduction. Charge transport is ballistic over long distances; the material exhibits large quantum oscillations and large and nonlinear diamagnetism. Graphene conducts heat and electricity very efficiently along its plane. The material strongly absorbs light of all visible wavelengths, which accounts for the black color of graphite; yet a single graphene sheet is nearly transparent because of its extreme thinness. The material is also about 100 times stronger than would be the strongest steel of the same thickness.

Scientists theorized the potential existence and production of graphene for decades. It has likely been unknowingly produced in small quantities for centuries, through the use of pencils and other similar applications of graphite. It was originally observed in electron microscopes in 1962, but only studied while supported on metal surfaces. The material was later rediscovered, isolated and characterized in 2004 by Andre Geim and Konstantin Novoselov at the University of Manchester, who were awarded the Nobel Prize in Physics in 2010 for their research on the material. High-quality graphene proved to be surprisingly easy to isolate.
The global market for graphene was $9 million in 2012, with most of the demand from research and development in semiconductor, electronics, electric batteries, and composites.
The IUPAC (International Union for Pure and Applied Chemistry) recommends use of the name "graphite" for the three-dimensional material, and "graphene" only when the reactions, structural relations or other properties of individual layers are discussed. A narrower definition, of "isolated or free-standing graphene" requires that the layer be sufficiently isolated from its environment, but would include layers suspended or transferred to silicon dioxide or silicon carbide.

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  1. J

    A LCAO graphene orbitals wave functions

    Hello, My name is Josip Jakovac, i am a student of the theoretical solid state physics phd studies. First I want to apologize if my question has already been answered somewhere here, I googled around a lot, and found nothing similar. My problem is that I need to apply TBA to Graphene. I went...
  2. Making Graphene could KILL you... but we did it anyway?!

    Making Graphene could KILL you... but we did it anyway?!

    Today's video shows you how to produce your own graphene which should only be done very carefully and with previous experience.
  3. Synco

    Big doubt about graphene in batteries

    Well people i'm looking electric Motorcycles. And the same seller it's selling a 72V50Ah battery and a 72V60Ah battery, both IN THE SAME WEIGHT, every battery in the shop occurs the same. So or we have a factory mistake, scam, witchery .....or...graphene in the lithium. I have been reading that...
  4. gggnano

    Can I get any macro object of very small thickness such as 10 nm?

    I know graphene particles are small but how do I work with them separately? If you tell me easy-to-accomplish way for handling a single grain of graphene at home...OK. I was thinking about something like a very thin sheet of graphene, but in quantum measurements they are huge: micrometers and I...
  5. J

    Graphene/GO-based elastic material

    Is it currently possible to create a Graphene or Graphene Oxide-based polyester film, but with significantly lower helium permeability than currenlty avalible materials? What would be the best way to create such a material and what type of processes and equipment would be involved in the...
  6. F

    I Momentum/angle values of eigenstates in a graphene system

    I am trying to differentiate between states in a quantum system of graphene with open boundaries in one direction and periodic boundaries in the other direction. The eigenstates have been simulated with the eigenenergies, but how would I proceed in calculating the expectation value of the...
  7. Mohammad-gl

    MATLAB Graphene band structure Matlab code

    I have this code for 3D band structure of graphene but i can't understand why while graphene first brillouin zone is hexagonal but here a rectangle form of first brillouin zone is used? E0 = 0; % coloumb integral V = -2.7; % hopping integral [eV] acc = 1.41; % c-c bond length [Angstrom]...
  8. bob012345

    A Rippling Graphene Harvests Thermal Energy?

    It is claimed 2D Graphene sheets can be used to harvest thermal energy while being at the same temperature as the surroundings in seeming contradiction to Feynman's *argument (in the popular accounts). However, the academic papers referenced below make the claim everything is well within known...
  9. S

    ARPES calculations on graphene

    Consider the attached screenshot. The work function of graphene is assumed to be 4.5 eV. 1. Does the work function correspond to the binding energy ##E_B## as given on Wikipedia? What is ##E## in ##E−E_F## in the graph on the right? 2. "...the Fermi level at the K-point..."; is this the point...
  10. H

    I Graphene - Armchair vs Zigzag - Semiconductor?

    I have a question concerning the differentiation between the zigzag and armchair pattern of graphene. Specifically concerning the fact that zigzag edges produce metallic properties and armchair edges producing semiconducting/metallic properties. How does this relate to the orientation of...
  11. Redmagic

    Physicists build Graphene Thermodynamic Battery

    I read an article in Science Daily 'Physicists build circuit that generates clean, limitless power from graphene'. Can someone explain how to take this from the physics science experiment to the engineering prototype and implementation stage? Is this technology going to revolutionize the mobile...
  12. F

    Python Problem with coding the band structure of graphene nanoribbons

    Hi, I have a Matlab code for calculating the band structure of graphene nanoribbon which is working fine, but I wanted to convert it to python and I've done it. I guess I made a mistake somewhere because the plot is totally wrong. Could someone check it for me, please?
  13. P

    A Graphene wavefunction expressed in tight binding form

    In the framework of tight binding approximation, does the wavefunction for atom A (or B) has two spinorial components(2 components) in "real space"? If so how does this spinorial component propagate in the graphene?
  14. A

    A DFT calculations for metal oxide semiconductors and graphene oxide

    I am doing experimental research on metal oxide semiconductors and graphene oxide, I also want to do some theoretical analysis. I am new in theoretical, so I need guidance how to proceed with the simple calculations, like DFT. Is there any authentic book with examples? and also is there any...
  15. Sunny Huang

    A How to calculate the interband velocity matrix in a graphene system

    In graphene system, the velocity operator sometimes is v= ∂H/ħ∂p, and its matrix element is calculated as <ψ|v|ψ>, i.e., v_x = v_F cos(θ) and v_y = v_F sin(θ) [the results are the same with Eq. 25] for intraband velocity. Recently, I see a new way to calculate the velocity matrix (Mikhailov...
  16. F

    Can graphene be usefull as armor against HEAT rounds?

    From what I understood from articles like this(https://scitechdaily.com/microbullets-demonstrate-graphenes-energy-absorbing-strength/) graphene is really good at distributing the energy from impacts over larger area and can even turn into diamond-hard material called diamene upon impact when...
  17. VictorMedvil

    Synthesis of Titanium Oxide Nanoparticles Coated in Graphene Oxide

    I wanted to know the finer details of synthesis of Titanium Oxide Nano-particles coated in Graphene Oxide, what exactly does creation of these nano-particles entail?
  18. T

    Low Cost Graphene Produced

    Researchers at Rice University in Houston, Texas, USA have found a low cost way to produce Graphene from just about any Carbon based material. They flash heat it to around 3 000k by electrical discharge and it cools into single-layer flakes...
  19. S

    A Graphene's Hubbard U and nanotube's U

    PhysRevLett.106,236805 (2011) seems to state that Graphene has U=9.3eV and PRB 55-R11973 (1997) states that nanotube has U=u/N. However, it's not unusual for them to be hubbard U systems
  20. K

    B Will graphene become a wonder material for future inventions?

    I want to know more about upcoming revolutions
  21. forever_physicist

    A Inequivalent K and K' points in graphene

    Good evening to everybody! I have a question concerning monolayer graphene. In all the papers I read it is well specified that K and K' in graphene are not equivalent points, but I didn't find anywhere where is the difference between them. Can anybody tell me where this difference is coming...
  22. T

    Graphene and Newtonian mechanics

    I am writing a paper for "Dynamics and statics" course. I am really interested in Graphene. I am not if this is a good topic for this specific course. Any suggestions? Thank you in advance
  23. SpinzTronics

    Help searching for SAMs (self-assembling monolayers) for a project

    Does anyone know of a self-assembling monolayer that can bind to triethylamine,deposit onto graphene/TMD by evaporation, and that has "low toxicity" (that I could use in the lab)? P-dopants could only help dope one side of the material and TEA would react on the other but that is very hard to...
  24. J

    A Graphene Spin Relaxation: Getting Started

    Recently, I want to study spin relaxation in graphene, but I don't know how to get start. Can anyone tell me which papers should I read for beginning so that I can have a deeper insight in it theorically and experimentally ?
  25. Sadek

    Permitivitty of graphene

    i'm working on a project about the surface plasmon in graphene. i found on some articles that we don't use Drude model to calculate permitivity on graphene but they didn't mention what's the right model ! can you help me please and give me the relation that link links between permitivity and...
  26. .Scott

    B Graphene Stacked at 1.1 degrees Superconducts

    It's an interesting article just published in Nature: https://www.nature.com/articles/d41586-018-07848-2
  27. Magnetosphere

    Simple method for testing graphene

    I saw this video for testing whether one has graphene or graphite and was wondering about the authenticity of the method. By mixing 50%h2o and 50%gasoline the graphene should separate/settle in between the two within a second after shaking. Here are some pictures of my own experiment before...
  28. Javier Lopez

    B What is the work function of graphene sheets?

    I have found different values depending where is read. I should like have a graphene sheet on copper to be used in a ionizer to generate lots of electrons
  29. I

    B Graphene Spinning Speed: Theoretical Max RPM of 1m Radius

    Theoretically, how fast in RPM can a circular sheet of graphene of radius 1 m spin without tearing apart?
  30. D

    B Can graphene be used as a template for graphene growth

    Hi, If I had a silicon carbide wafer Si-face with a monolayer of graphene on it, then spin-coat it with single wall carbon Nano tubes (CNTs) onto the graphene and then annealed it, would the CNTs bond to the graphene under them? Or would they still partially unzip and decompose forming a sheet...
  31. A

    Graphene simulation in Comsol Multiphysics

    Hi All How can i simulate Graphene in Comsol? I am using semiconductor module . I s it correct to use Drude model? Drude model is in RF module but my simulation should be run in semiconductor module. How about Kubo formula?(for optics application or no?)
  32. Nod

    A Charge density of carbon nanotubes and graphene

    Hi everyone! I'm trying to solve the following problem: given the charge densities of carbon nanotubes and graphene, the charge density difference of 2 systems must be found. So I need to unfold in some way the nanotube and compare it charge density with the graphene's one. But how this...
  33. M

    Macross/Robotech Space Fold

    In the anime series Super Dimension Fortress Macross (Robotech in the US), they fold space to travel vast distances. In the first episode, the humans plan an emergency fold to jump from Earth to the moon. Supposedly you shouldn't fold space too close to a planet. Their mistake sends them...
  34. S

    How do I get this interface condition?

    Homework Statement I have an infinitely long cylinder of a dielectric material, surrounded by another dielectric material and coated with graphene which has surface conductivity \sigma, implying it has a superficial current. The sheet of graphene is very thin, and the dielectrics are asumed to...
  35. S

    Interface conditions on a graphene interface

    Homework Statement I'm trying to do all the calculations for the attached paper, and I'm having trouble with the boundary conditions for P polarization. My question is, how can I arrive to those conditions? The problem is 2D, an infinite dielectric cylinder coated with a layer of graphene...
  36. D

    How does Ethyl isopropyl ketone affect graphene sheets?

    Hi my name is Chris and I was wondering how dose Ethyl isopropyl ketone effect graphene's conductive properties? graphene is a 2D material made from carbon atoms arranged in a hexagonal pattern ( A honeycomb crystal lattice) I was reading the graphene hand book and it said that graphene sheets...
  37. M

    Gas adsorption for (BET) surface area of graphene oxide based thin films

    I am using a Micromeretics ASAP2020 machine. The sample is ~25mg of reduced graphene oxide based film. The problem is I am getting adsorption isotherms showing negative volumes of adsorbate (N2) entering the tube as P/P0 increases. The sample was degassed prior to testing at 250°C for 3...
  38. S

    A 'Massless' Electrons in Graphene

    So I've read that electrons traveling inside a sheet of graphene are said to travel "masslessly". I'm interpreting this as meaning "zero apparent mass" and not zero actual mass. Presumably, the graphene doesn't somehow weigh less than the sum of its constituent electrons and nuclei. But given...
  39. J

    Standard Enthelpy of formation of Graphene

    I am curious as to what the Standard Enthalpy of formation of Graphene is. I've noticed several highly technical papers on this subject but I got lost in the abstruse math and terminology. I am interested in the Standard Enthapies o both single layer and multi-layer graphene. I will be happy to...
  40. G

    How to calculate the current in a 400 nm wire of graphene

    Hi, I need to calculate the current in a 400nm piece of graphene. Can some one help me please? I found online that graphene has electron mobility of 200,000 cm^2/( V s). My best attempt is as follows. Using the equation vd = uE where E is the magnitude of the electric field applied to a...
  41. S

    I How can I obtain the reciprocal lattice of graphene?

    I have a question about reciprocal lattice of graphene. When we see LEED pattern, we can know that reciprocal lattice of graphene is honeycomb. But how can we know theorically that it is honeycomb? Hexagonal lattice or other bravais lattice has just lattice vectors which don`t contain baises. So...
  42. C

    Tensile Strength of reduced graphene oxide?

    Does anyone know the tensile strength and other mechanical properties of reduced graphene oxide? I know that it has some similarities to both graphene and graphene oxide, but I can't find any data on its tensile strength.
  43. M

    A DFT modelling of graphene, fullerenes, nanotubes etc

    Hi all. Does anyone here have any experience modelling graphitic materials using DFT based software (eg VASP)? I am looking to utilise some simulation results in conjunction with applied research on these materials. The focus is really the applied stuff, and I have very little background in...
  44. S

    A Kelvin Units: Help Understand Optics of Graphene

    Hey! In https://www.researchgate.net/publication/230937856_Optical_properties_of_graphene [Broken] article (Optical properties of graphene) I found out the frequency is expressed in Kelvins. Could you help me with it - how did the author do this unit transformation? Thanks in advance!
  45. T

    I How is Graphene's Hamiltonian rotationally invariant?

    Graphene's Hamiltonian contains first order derivatives (from the momentum operators) which aren't invariant under simple spatial rotations. So it initially appears to me that it isn't invariant under rotation. From reading around I see that we also have to perform a rotation on the Pauli...
  46. S

    A What is the charge neutral point?

    I have a question about definition of charge neutral point. I`m reading some article about trilayer graphene, and this term, charge neutral point, is used in the article. I googling this word, but I can`t find something which can tell me what it is. In monolayer graphene, what i found by...
  47. H

    I Why perfect graphene has nonmagnetic state?

    I'm major in chemistry my undergraduate.. and not good at Physics, Solid states... etc. I know pure graphene has two sub-lattice because it has two carbon atoms.. and something basic properties. then, why perfect graphene(no vacancy) is in nonmagnetic?
  48. ScrollPortals

    What does it take to rush ahead of commercial factories? (graphene)

    Cheaper ways to make graphene I want to try making my own computing parts with graphene. What are we capable of now with graphene? What parts can we make? What computations can we do? Do we have circuit board limitations?
  49. I

    Calculate Electrical Pressure Capacity with Graphene Work Function

    Is the reciprocal of the work function of ' Graphene ' a usable tool for the calculation of the electrical pressure * capacity or even an indicator of co-conductivity of a given area of (magnetically oriented) Graphene in relation to a substrate material which is also conductive ?
  50. A

    Congratulations Mechanical Engineers

    People spend so much time drooling over the millions or even billions made by software tycoons and their sometimes very crappy software, that we may forget about the tangible accomplishments of mechanical engineers. Here is a beautiful example. Do you have more...