Graphene Definition and 136 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. 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...
  2. 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...
  3. 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...
  4. 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
  5. 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...
  6. 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...
  7. 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
  8. 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...
  9. 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...
  10. 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...
  11. 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...
  12. J

    Standard Enthalpy 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...
  13. 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...
  14. 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...
  15. 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.
  16. 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...
  17. 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...
  18. 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?
  19. I

    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 ?
  20. 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...
  21. C

    I Graphene substrate

    I have looked on the internet but not found a clear anwser. can graphene sutstane its 2-dimensional form witout anny help froms substrades? tanks for helping ^^
  22. R

    I Carbon in air to graphene?

    Is it feasible to turn the abundance of carbon in the atmosphere into graphene, given it is an allotrope of carbon and would it be worth the trouble?
  23. N

    A Is graphene a Weyl semimetal?

    I'm recently interested in the topological/Weyl semimetals, but I'm not an expert on the theory. Most papers just define Weyl semimetal as a material that have pairs of Weyl points with opposite Berry curvature. Here in graphene, the Berry curvature of the Dirac cones at K and K' point is also...
  24. S

    A Wavefunction matching two different H, not just V

    Can the basic techniques of wavefunction matching that one would use to calculate the transmission through a step barrier potential and the Dirac hamiltonian of graphene be used for a situation where instead the fermi velocity changes in a step like fashion. i.e. instead of a Hamiltonian like...
  25. Harry Smith

    I Will ethanol destroy double layered graphene?

    I am doing a lab and we get silver epoxy resin on our double layered graphene sample where we didn't want it. We can take off the silver paint using ethanol but worry it may destroy the thin layer. Will ethanol be okay to use? Are there any suggestions on what to use?
  26. A

    Making a Graphene suit

    So I have heard about graphene and its properties recentlty and more specifically its ability to resist tearing. With this in mind (and a video from the YouTube channel "Film Theory") I believed it was possible to stack layers of graphene so that they can resist things like bullets. But I...
  27. thund3rcz

    I Effect of SAM physisorbed on graphene - some questions

    Hello everyone! :) I'm sorry that I'm posting something that might be obvious, but I'm still struggling to capture all the concepts behind the fundamental physics of this model. Let's say, I have a 2D sheet of graphene, on which, theres a physisorbed layer of molecular dipoles (vdW bonding, no...
  28. T

    Graphene questions

    Hi, I haven't had any chemistry exposure for over a decade, (I have some semi-conductor and quantum mechanics experience though) I was wondering: (to my vague 'knowledge') If graphite is just made of many overlapped graphene sheets, then why isn't graphite conductive? Also, if graphene is a "2D...
  29. E

    Graphene structure obtaining code

    I want to write a octave code(It can be another language I want to know how should I think to write a such a code ) to obtain graphene structure like in the figure. This code should give me a graphene sheet which in size I want when I enter the position of the atoms in the lattice.I think that...
  30. J

    What laser should I use?

    If I were to replicate this experiment but was limited to the purchase of only one laser which frequency and what power should I choose? I know the research team that conducted this experiment purchased their lasers from but they unfortunately...
  31. T

    Book recommendation on fundamental physics in Graphene

    I am a condensed matter grad. student, but do not work on Graphene. I am interested in learning about the fundamental physics in graphene (e.g. the need to use Dirac equation to represent the motion of electrons). I know that many books are there, but not all are geared towards fundamental...
  32. Benevito

    Solid State Introductory book on graphene?

    Can someone recommend a good book on graphene?
  33. F

    Why is graphene placed in a cryostat in research?

    I have been told when making transport measurements of graphene it is usually placed in a cryostat and cooled to ~ 4K. However I cannot find any sources that back this up and don't fully understand why it is done in the first place. My thoughts are that it is to measure the carrier mobility...
  34. I

    Compute subband structure of graphene

    There’re 2 ways to calculate the subband structure of graphene nanoribbon using tight-binding model, for Zigzag chain: The first one is to diagonize the Hamiltonian $H = H_0 + H_10*exp(i*k_x) + H_01*exp(-i*k_x)$ and obtains the eigenvalues. The second method is just diagonize the Hamiltonian in...
  35. S

    What's a general algorithm to build a supercell from a primitive cell?

    Basically, I've written some code that take as inputs 1)Basis vectors 2)lattice translation vectors and computes the structure factor of the basis, producing a diffraction pattern. I'd like to begin incorporating subtle differences between atoms, so I want to compute the structure factor of...
  36. D

    In order to generate electricity is copper required?

    Copper conducts electricity and so does other metals like silver. Now a new material is coming to play which is graphene, But I was wondering in order to generate electricity must it be in copper coils? Can it be in silver coils, graphene coils? ^.^
  37. O

    Quastion about K-points and energy cutoff

    Dear All, I have three questions about the relation between the K-points and energy cutoff. The first one is : how many k points should I use in my theoretical calculation to get a good result in lattice constant and the converge of Emin especially for using DFT? The second one is : What is...
  38. J

    Electric Car Advances

    A lot of people have been arguing that TSLA's stock/the company in general wont take off because the demand is above the battery technology at this time. I'm a junior in college studying physics but will probably either switch to finance and do stocks because i like it more or i was double major...
  39. D

    Post-B.S. Struggles

    I'll just launch into it: I graduated recently from Temple University with a B.S in Physics, GPA 3.83. I worked in three labs, one semester each, during my studies: one for pay, one volunteer, and one for credit. In the first, I did analysis for Mossbauer spectroscopy; in the second, I produced...
  40. A

    Density of states

    Homework Statement Using the dispersion relation at the Dirac Point calculate the electron density of states for graphene in both the valence and conduction band. Homework Equations ρ = density of states = k2/pi2 The Attempt at a Solution I looked up what Dirac Points...
  41. maverick_starstrider

    Right Qualifications for DFT in Industry

    Hi All, I'm finishing up my PhD in Computational Condensed Matter. I've worked almost exclusively in spin systems using things like Monte Carlo and Exact Diagonalization. However, my specialty is in producing high-quality, high-performance, often parallel research codes (i.e. none of my...
  42. S

    Night vision based on OLED technology

    Hello, I started this topic to discuss interesting new night vision technology that was presented on TED talks. Old, expensive and bulky IR (or other light spectrum) IIT amplifier could be replaced with very thin OLED based, cheaper and low power consuming image intensifier which was developed...
  43. L

    Derivation of Height Function given an angle

    Hey everyone, I'm currently doing research at a University, I've been working on a problem for a few hours and wrote up a quick paper that shows my derivation of a certain height based on an angle. Basically the experiment is looking at optical properties of graphene, but for this to happen we...
  44. A

    Possible application of Genetic Algorithms

    Ok so I have a view ideas in mind for a project I was planning on doing involving genetic algorithms for my high school science fair class. I do have 3 mentors one a mathematician, a computer scientist who focuses on GAs, and a physicist who focuses on nano structures. here where I live, but...
  45. B

    Standardized Elephant

    Recently, reading an article about graphene, it was disclosed that a sheet of graphene the thickness of a piece of plastic wrap could support the weight of an elephant balanced on a pencil. Beyond the fact that I highly doubt anyone got an elephant (although good at balancing tricks I have seen...
  46. D

    How do you specify your intererests in physics when you're a freshman

    Hello, I'm interested in research and development of either fusion power generation or graphene based nanoelectronics. One of the things I like about these areas is that they are in the imminent stages of development and I will probably see them developed in my lifetime. My issue is that...
  47. D

    Carbon nanotube exoskeleton

    Can we make exoskeletons out of CNTs? I have a few questions 1. Do CNTs expand when electricity is applied or you have to put wax betwen them? 2. Can we produce enough nanotubes to make a full-body suit? 3. Is graphene suitable for an armor? Some say that when you put a elephant on a...
  48. C

    Career in Simulations

    I've gotten really interested in CFD and DFT recently. I have a BS in Chemical Engineering and will be 25 in about a month. Been working in the oil industry for the last 2 years and before that I worked in a carbon nanotube and graphene 'factory' for lack of a better term that I can come up with...
  49. V

    Help with the Tight Binding model

    Hi everyone, I'm trying to fit the Tight Binding molecule for a more complicated system, so I'm first trying to understand it for a simpler one, graphene. I've read several guides but they're all confusing me. Right now, I'm trying to understand the graphene example on this site. My biggest...
  50. S

    The theoretical Augmentations

    The theoretical "Augmentations" One thing that is somewhat common and has to do with medical science and my interests are augmentations, robotic, nano-technological, or even sometimes genetic enhancements. In the science fiction representations people can outperform human strength and speed...