thickness of graphene

kevinisfrom

Hello,

I was just wondering what the theoretical thickness of single layer graphene is?

Thanks in advance for any feedback.

NeedBranes

A single layer of graphene would be one atom thick, carbon.

kevinisfrom

Do you know the answer in Angstroms?

NeedBranes

1 Angstrom is .0000000001 meters, carbon is 1.54 Angstroms

kevinisfrom

a carbon atom is not the same thing as graphene. do you know the thickness of graphene in Angstroms?

Greg Bernhardt

This paper might give some clues
http://arxiv.org/pdf/0812.0690.pdf

NeedBranes

A carbon atom is not the same thing as graphene but a "sheet" of carbon atoms is. 1 layer thick sheet of graphene is one atom thick. Wrap it in a cylinder, you have a carbon nanotube, put it in a ball you have a buckyball, stack one sheet of graphene on one sheet of graphene you have graphite. I could be wrong, I am no expert.

kevinisfrom

Hi Greg, thank you for the reply. Your link is an experimental paper. I was hoping for the theoretical value of graphene's thickness, and also the interlayer spacing between graphene sheets in graphite.

kevinisfrom

There are sp2 bonds between C atoms. It's different from an isolated atom.

Kholdstare

Thickness is a confusing quantity. You should define how you relate thickness of something with actual length between two particular points in that something.

Again this depends on what is the definition of thickness.

AFM depends on Coulombic repulsion to measure thickness. Its hard to tell exactly where is the surface of the layer. Or how do you define the surface of the layer.

True in a sense. The "thickness" of graphene is one carbon atom "thick".

kevinisfrom

Thanks for the replys. I know there is a widely accepted theoretical value for the thickness, considering all the atom-atom interactions and whatnot. It's just a number. I understand there is a lot to consider when doing AFM scans, but there should be a simple answer to this question theoretically. I knew it once, but have since forgotten.

Kholdstare

I can give a very naive answer. Try C-C bond length/2 as the radius of the atom. Then the thickness becomes just C-C bond length. Of course it complicates with the nature of bonds or other elements etc.

Also, you can use non-bonding p-orbital electrons of sp2 for rough thickness calculation. Just take the mean radius of their orbital. But then again it will register different in AFM as after bonding with AFM tip, the electronic configuration might change.