Field effect transistor made of graphene: how does it work?

[Naamean]

Hi folks,

I am desperately trying to understand how this device is working... I would like to precise that I understand how field effect transistors/junctions based on p- and n-types semi-conductors are working (with a p-type gate it is ok; with a n-type gate it is already less ok since holes transport is not intuitive to me).

I am trying to make a parallel between these "conventional" transistors and the one made out of graphene described for the first time in Novoselov's paper of 2004 ("Electric field effect in atomatically thin carbon films"). But I don't see what happens between the graphene and the silicon.

Could anybody please help me on this?

 

[TeethWhitener]

Well, graphene doesn’t have a band gap, so FETs don’t work very well. The field effect referred to in the paper by Geim and Novoselov has to do with the fact that the electronic density of states at the Fermi level is zero in graphene (and nonzero everywhere else), so that if you have graphene that is completely undoped, its conductivity is quite low, but if you dope it even a little (say, by applying a gate bias), the conductivity goes up pretty steeply.