Graphene Definition and 212 Threads

A new conjecture postulates that it may be possible to "create" mass through relativistic effects on leptons inside of graphene, when it is rolled up into a nanotube: http://www.technologyreview.com/blog/arxiv/25914/?p1=A4 Gee, does that imply that it could be possible to manipulate or...

Hi. After i first heard about graphene, a few ideas started forming in my head. but before i can even tell if they would work or not, I need some information on graphene i can't seem to find anywhere else. For one thing its molar mass and another, its physical strength.

Could someone please explain why the thread https://www.physicsforums.com/showthread.php?t=435072"? Not that I have anything against General Physics, but it seems like maybe topics like "Cleaning your PC with a vacuum cleaner", "Rock On Rod Stewart", "My Air Mattress as a Pressure Vessel"...

i am vinoth. i am doing research project related to how we can vary the band gap in graphene nanoribbon and use it to form transistor. now only i started for literature survey related to how we can vary the band gap in graphene nanoribbon.i need some guidance from our friends.i am waiting for...

Researchers have developed silicene, atom-thick silicon sheets similar to graphene: http://www.knoxnews.com/news/2010/aug/25/silicene-new-form-silicon-might-speed-microcircuit/ http://apl.aip.org/resource/1/applab/v96/i26/p261905_s1?isAuthorized=no How similar could atom-thick...

can anyone explain what is d band and g band in the Raman spectrum of graphene?

I have done the computations of band structure of cobalt adsorbed graphene. In 3x3 supercell of cobalt adsorbed (one cobalt atom) graphne, there is opening of band that is gap between conduction and valence band but there is no gap in 4x4 supercell of cobalt adsorbed graphene. I've done this in...

I know that graphene is a far more superb conductor than copper, but I'm trying to compare their weight difference. I mean, let's take an example: A copper busbar that is 7kg with resistance of 2 micro-Ω can carry a lot of current(in kA), I assume a much lighter(possible less than a kg) graphene...

I'm going to see my girlfriend for the first time since the summer began. Any ideas for a nerdy thing to do when I see her or gift to give her? I have access to old, used, crappy graphene if you could think of a way to use that.

Hi, I just read a paper on graphene's basic properties and it says that since current density J is given as J=q*n*v where q is the elementary charge, n is the electron density and v is the Fermi velocity of electrons and for graphene n=6*10^12 cm^-2 and v=10^8 cm/s, the current density...

What is graphene from a physics standpoint? Why do I keep hearing that graphene is considered to be such a major breakthrough? How is graphene going to transform the world?

I'm a third year physics undergraduate and I want to make 3D Graphene - without spending a fortune. This is my background: I found this review article by Jiang and Fan (Design of advanced porous graphene materials: from graphene nanomesh to 3D architectures) to be very helpful. From what...

why do we make composites with graphene oxide not with graphene ? if there is a problem to do composite with graphene ?

Hi. According to the attached article I couldn't draw fig1 with eq1 using mathematica.

All of the sources I have found for this online have been wildly unclear. Many use the phrase "Fermi energy" to refer to the "Fermi level" (which is emphatically not what I'm looking for; I want the Fermi energy as defined in this Wikipedia article: http://en.wikipedia.org/wiki/Fermi_energy )...

Published values for the room temperature thermal conductivity of graphene vary from ~2000 W/m*k to 5600 W/m*k, for freely suspended samples. The large discrepancy shows the sensitivity of graphene to lattice defects (contact with substrate, edge defects, etc.) Thermal conductivity increases...

Im astonished with graphene's properties. But currently I am most interested with its conductive properties, I assume graphene has an extremely low resistance? If so, can it compete with superconductors? I mean, since SC break at powerful magnetic fields hence they have a limit when carrying...

I've tried searching for it but while there are a lot of hits on the fact that graphene's conductivity is high, there seem to be very few on how the conductivity is actually measured. Would you use the same method as you do with metal wires? Using cross sectional area, length, an ohmmeter...

I had a random idea about the effect of cosmic rays on graphene's conductivity. I found out that cosmic rays would create defects in graphene over time. How many of these defects would significantly reduce the conductivity of graphene? How do I go about calculating how much time the graphene...

I had a random idea and wanted to know whether graphene could retain it's conductive properties after being exposed to cosmic rays. I know that graphene gets it's conductivity from the free electrons from its carbon atoms. I know that cosmic rays consist mainly of protons, with the minority...

Graphene research has been going on for a decade now, with huge numbers of researchers piling into get a cut of the magic. I have a PhD offer in the topic of the mechanical properties of graphene, and I am pondering whether to accept and join the bandwagon myself. I would be interested to...

Hi, Homework Statement I have two questions, in fact, both involving 2D graphene: (1) How may I determine the number of nearest neighbours in a primitive cell of graphene? (2) Given that graphene has linear energy dispersion near the fermi level and the dispersion is given by E=(hbar)vF|k|...

Homework Statement French physics teacher have tried to find out the script of this video but would appreciate the review from a native speaker. Thank you for your help. http://vfsilesieux.free.fr/graphenevideo2/video.swf

Hi everyone, long time lurker, first time poster. I've just begun a phd which involves nanoribbons (a small strip of a 2D material connected at either end to a larger 'bulk' section of the same 2D material). A question has occurred to me. These nanoribbons look a lot like a piece of string...

Hi as an undergrad Physics student learning quantum mechanics for the first time, I'm having a hard time wrapping my head around quantum tunneling, why does it happen, why can it happen? I was also reading that Graphene exhibits tunneling as well, could someone explain this?

Hi, * There is no bandgap for zigzag GNRs if the spin is neglected. In some of the studies in the literature, spin is neglected and analyses are done considering zigzag GNRs as metallic. * In another group of works however, it is argued that spin-polarized bandstructure of zGNRs have small...

Hi, I got a graphene dispersion on ebay but the graphene flakes cumulated at the bottom of the bottle. I'm trying to mix it and then solve in water using an ultrasonic cleaner but the flakes do not dissolve in water? How can I dissolve it so that I can obtain a large scale graphene by...

Hi, I just got a small bottle of graphene dispersion (not GO) on ebay and put a small drop on a ciruit board as shown in the pic. I expected to measure a finite resistance because graphene is a conductor as much as I know. But it seems to have zero conductance from what I read on the...

Carbyne is comprised of chains of double- and triple-bonded carbons and is believed to be stronger and stiffer than graphene, nanotubes, or diamond: http://www.technologyreview.com/view/518301/new-form-of-carbon-is-stronger-than-graphene-and-diamond/ To me, this reminds of Arthur C Clarke's...

So lately (meaning the past few years) I've been hearing a lot about graphene and how it's amazing. It's apparently super strong, has a high conductivity and many other amazing properties. It was the subject for which a nobel prize was won, and it supposedly will change the future. I can't...

This amazing study suggests that the material Graphene may make the internet one hundred times faster,here some links http://www.bath.ac.uk/news/2013/07/12/graphene-internet-speed/ http://prl.aps.org/abstract/PRL/v110/i21/e217406 what do you think of it?

What method can be used to make large macro-sized sheets of graphene? There have been recent articles on research showing that patchwork quilts composed of large sections of graphene have nearly the same bulk strength as pure graphene would...

I have been hearing about the possibility of a graphene super capacitor for quite some time now, but it still seems they are not readily available. Is there anyway for me to get my hands on one? Would it be possible for me to buy/make one practical enough to replace a AA battery? What size...

Hi, I'm a 4th-year physics undergrad and I have a question about calculating the band structure of graphene using tight binding. Following the calculation here...

I've read that it's several times stronger than steel. I haven't read anything about its stabbing resistance against the tip of a knife, though. Does anyone have any ideas on this subject? Could a human stab through an inch of it?

I am trying to reproduce Kaner and El-Kadys Graphene based electrochemical capacitors (ECs). The process reduces Graphite-oxide (GO) to laser-scribed graphene (LSG) using a lightscribe. I think I have figured out a way to produce the graphite-oxide from watching a couple of great videos on...

Homework Statement I want to know why Graphene has the properties it has, I am really struggling to find out why graphene has the properties it does. Strength, I know graphene contains covalent bonds which are strong and that it has a hexagonal lattice structure. Electrical conductance I know...

A lot of hype is out there about both of them (especially the latter) and I was wondering if there is more concrete information about them other than the news IBM posted on a circuit 2 years ago and the patent war about Graphene transistors involving Samsung and IBM among others. Also, what's up...

I heard that people envision strong structural materials made out of graphene, but I heard it may weaken when being stack in layers. Is graphene viable for macroworld structural engineering or is it only suitable for electronics and similar applications?

Hello, I was just wondering what the theoretical thickness of single layer graphene is? Thanks in advance for any feedback.

We've been making things out of graphite for ages, which certainly has its uses, but interest in graphene has just started to take off recently. It's hailed as a miracle material and it seems that it was right under our noses all along - how come it took such a long time to be discovered?

everyone knows, there exists the relation between the group velocity and energy dispersion. a question is how to expression the relation between the velocity and momentum k? it seems that the Dirac electron in graphene is massless.

Hi to everyone I'm working on mu thesis with this title: Calculation of graphene conductivity in the semiclassical regime And also I should calculate it with Boltzmann equation Is there anybody who can guide me for where to start and even how to calculate the graphene conductivity using...

I have had a question on my mind for a while now. Would it be possible to make a graphene supercapacitor using the scotch tape method for making graphene? Except unroll the entire roll of tape and cover it in graphite and then press it against another entire roll of scotch tape, peel off and...

Hello- I am trying to find a reference describing the z(or c) component of the basis vectors for graphene. I seem to recall that there is a slight bend such that half of the atoms lie slightly above the plane. However, every paper I have found references the perfect 2D lattice of Graphene...

Hi Everyone, I have recently made some graphene on copper via a chemical vapour deposition process. I have also managed to have a peep under an SEM at this. I do see what I believe to be monolayer graphene. I am very sure the contrast I see is graphene due to the growth patterns, ranging from...

In graphene the fermi level can be moved into the conduction or valence bands by applying an external electric field, allowing conduction by either holes or electrons. My question is where do these new electrons come from (or go to in the p-type case)? Also, why is this special to...

Graphene -- Green's function technique Hi, I am looking for a comprehensive review about using Matsubara Green's function technique for graphene (or at least some hints in the following problem). I have already learned some finite temperature Green's function technique, but only the basics...

Hello! I am a student and have just started studying about graphene. However I am having quite a lot of problems understanding the crystal structure, specifically, I am unable to place certain terms. These being : 1. Basis vectors.(I do understand what a basis vector...

Inelastic scattering of Xray photons from electrons give them a wavelength shift, the Compton effect. The shift is inverse proportional with the mass of the electron. Now, if visible light scatters inelastic from electrons in graphene what will be the wavelength shift? The electrons in graphene...