The 10 strangest facts about graphene

By Dilip -

When first discovered, graphene was odd. Now odd is too small a word for a material seemingly set on winning all the records a material can win... what is it that makes this material so remarkable? Here are 10 of the strangest facts about graphene.
1. Strength
"The most amazing thing to me about graphene is its strength. This is a sheet of atoms that you can pick up. That blows my mind."
So says Professor James (Jim) Tour of Rice University in Texas, and who are we to argue with that? A sheet of atoms that you can pick up: say it out loud to yourself a couple of times.
Everyone you ask about graphene's amazing properties says the same thing: it is really hard to pick one feature when the material is so astonishing. So let's consider a few more of them.
2. No band gap
Graphene has no band gap. A band gap is the gap between the energy of an electron when it is bound to an atom, and the so-called conduction band, where it is free to move around. An electron can't have an energy level between those two states
This makes graphene a wonderful candidate for use in photovoltaic (PV) cells, for instance, because it can absorb photons with energy at every frequency — photons of different frequencies of light are converted to electrons with matching energy levels. A material with a band gap can't convert wavelengths of light that correspond to the forbidden energy states of the electrons. No band gap means everything is accepted.
This opens the tantalising possibility of highly efficient PV cells, but it's a problem if you want to use graphene in transistors, where you need the band gap to provide the isolation necessary if you want it to act as a switch that can be turned off.
It is possible to induce a small band gap in graphene by doping it. This is good enough for very fast amplifiers for radio work, but for transistors that make efficient logic circuitry you need a bigger gap.
3. Ballistic conduction
Yes, this is a really weird one: ambient temperature "unimpeded" conduction of electrons. Read more:

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