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Some graphene facts that I've found after a few minutes of research: - One million times thinner than paper, one atom thick, it's considered a 2D material. htt

by dm2 13y ago

Some graphene facts that I've found after a few minutes of research: - One million times thinner than paper, one atom thick, it's considered a 2D material. http://www.chemistryviews.org/details/ezine/4976821/Is_Graphene_Really_a_2D_Material.html http://www.chemistryviews.org/details/ezine/4976821/Is_Graph... - Strongest material, stronger than diamond. http://engineering.columbia.edu/even-defects-graphene-strongest-material-world http://engineering.columbia.edu/even-defects-graphene-strong... - Scotch tape was used to create a piece of graphene only 10 layers thick (I'm guessing that means ~10 atoms thick? wow) - Moves electrons ~200 times faster than silicon: http://www.samsungvillage.com/blog/2012/05/18/samsungblog-samsung-electronics-presents-a-new-graphene-device-structure/ http://www.samsungvillage.com/blog/2012/05/18/samsungblog-sa... - Transparent, only absorbs 2.3% of light. http://arxiv.org/pdf/1201.3071.pdf http://arxiv.org/pdf/1201.3071.pdf - Can't switch flow of electricity off? https://gigaom.com/2013/04/19/you-can-pluck-graphene-from-thin-air-but-then-what/ https://gigaom.com/2013/04/19/you-can-pluck-graphene-from-th... - Can repair itself if you dump carbon atoms on the hole, they snap into place. http://arxiv.org/abs/1207.1487 http://arxiv.org/abs/1207.1487 http://en.wikipedia.org/wiki/Graphene http://en.wikipedia.org/wiki/Graphene

danford 13y ago
I don't understand how it can be described as '2D'. If it were 2D you would be able to stack an infinite amount without the stack getting higher.
- tedsanders 13y ago
  "2D" describes the freedom of the electrons. They can move in X and Y, but not Z. This restricted freedom causes all sorts of unique electronic behavior never seen in 3D systems. You are certainly correct that graphene has height. Source: I am getting a PhD in 2D electron physics
- zacharypinter 13y ago
  My guess is that the people describing it as 2D are focusing on different properties of 2-dimensional space than you are and would agree with you that stacking it would increase the height.
- dm2 13y ago
  I think there is a different definition of 2D in the materials science field. http://www.mri.psu.edu/centers/2dlm/ http://www.mri.psu.edu/centers/2dlm/ http://www.chemistryviews.org/details/ezine/4976821/Is_Graphene_Really_a_2D_Material.html http://www.chemistryviews.org/details/ezine/4976821/Is_Graph... http://gigaom.com/2013/07/19/graphene-isnt-the-only-2d-material-here-are-a-few-others-that-could-change-material-science/ http://gigaom.com/2013/07/19/graphene-isnt-the-only-2d-mater... http://www.mrs.org/s13-cfp-o/ http://www.mrs.org/s13-cfp-o/
- Osmium 13y ago
  Loosely, it refers to the degrees of freedom an electron has in the material. For example, if you consider the 'density of states' – a quantity which can be thought of as the number of electrons at a given energy level – it has a different characteristic shape depending on whether the material is '1D', '2D', '3D' or even '0D': http://britneyspears.ac/physics/dos/images/Image441.gif http://britneyspears.ac/physics/dos/images/Image441.gif [As an aside, britneyspears.ac is a surprisingly good resource for a lot of basic solid state physics. You can find a full derivation of the above graph on there.] Edit: To illustrate, this next graph is the density of states for three different Carbon-based materials: graphite which is '3D', graphene which is '2D' and a nanotube which is '1D'. http://me3007.wdfiles.com/local--resized-images/thermal-and-electronic-properties-of-carbon-nanotubes/QuantDOS.jpg/medium.jpg http://me3007.wdfiles.com/local--resized-images/thermal-and-... [Source: Hone, J., Quantized Phonon Spectrum of Single-Wall Carbon Nanotubes, Science, 289, 1730, 2000 via http://me3007.wikidot.com/thermal-and-electronic-properties-of-carbon-nanotubes http://me3007.wikidot.com/thermal-and-electronic-properties-...] You can see how these curves are similar to the theoretically-derived curves in the previous graph.
KhalilK 13y ago
I think a combination of Graphene and superconductivity would be even more wonderous than each one of them!
- tedsanders 13y ago
  In fact, superconductivity can be induced in graphene by a proximity effect: http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.111.246805 http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.111...
tedsanders 13y ago
Nice list of facts. I would point out that although 2.3% absorption looks small, it's actually huge for just a single layer of atoms! So it's true that graphene is mostly transparent, but it's actually less transparent than almost any other single layer of atoms. That's why the title of your source is "high optical absorption in graphene." :)

by dm2 13y ago

danford 13y ago

I don't understand how it can be described as '2D'. If it were 2D you would be able to stack an infinite amount without the stack getting higher.

tedsanders 13y ago
"2D" describes the freedom of the electrons. They can move in X and Y, but not Z. This restricted freedom causes all sorts of unique electronic behavior never seen in 3D systems. You are certainly correct that graphene has height. Source: I am getting a PhD in 2D electron physics
zacharypinter 13y ago
My guess is that the people describing it as 2D are focusing on different properties of 2-dimensional space than you are and would agree with you that stacking it would increase the height.
dm2 13y ago
I think there is a different definition of 2D in the materials science field. http://www.mri.psu.edu/centers/2dlm/ http://www.mri.psu.edu/centers/2dlm/ http://www.chemistryviews.org/details/ezine/4976821/Is_Graphene_Really_a_2D_Material.html http://www.chemistryviews.org/details/ezine/4976821/Is_Graph... http://gigaom.com/2013/07/19/graphene-isnt-the-only-2d-material-here-are-a-few-others-that-could-change-material-science/ http://gigaom.com/2013/07/19/graphene-isnt-the-only-2d-mater... http://www.mrs.org/s13-cfp-o/ http://www.mrs.org/s13-cfp-o/
Osmium 13y ago
Loosely, it refers to the degrees of freedom an electron has in the material. For example, if you consider the 'density of states' – a quantity which can be thought of as the number of electrons at a given energy level – it has a different characteristic shape depending on whether the material is '1D', '2D', '3D' or even '0D': http://britneyspears.ac/physics/dos/images/Image441.gif http://britneyspears.ac/physics/dos/images/Image441.gif [As an aside, britneyspears.ac is a surprisingly good resource for a lot of basic solid state physics. You can find a full derivation of the above graph on there.] Edit: To illustrate, this next graph is the density of states for three different Carbon-based materials: graphite which is '3D', graphene which is '2D' and a nanotube which is '1D'. http://me3007.wdfiles.com/local--resized-images/thermal-and-electronic-properties-of-carbon-nanotubes/QuantDOS.jpg/medium.jpg http://me3007.wdfiles.com/local--resized-images/thermal-and-... [Source: Hone, J., Quantized Phonon Spectrum of Single-Wall Carbon Nanotubes, Science, 289, 1730, 2000 via http://me3007.wikidot.com/thermal-and-electronic-properties-of-carbon-nanotubes http://me3007.wikidot.com/thermal-and-electronic-properties-...] You can see how these curves are similar to the theoretically-derived curves in the previous graph.

KhalilK 13y ago

I think a combination of Graphene and superconductivity would be even more wonderous than each one of them!

tedsanders 13y ago
In fact, superconductivity can be induced in graphene by a proximity effect: http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.111.246805 http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.111...

tedsanders 13y ago

Nice list of facts. I would point out that although 2.3% absorption looks small, it's actually huge for just a single layer of atoms! So it's true that graphene is mostly transparent, but it's actually less transparent than almost any other single layer of atoms. That's why the title of your source is "high optical absorption in graphene." :)