Monday, May 20, 2013

Graphene is making physics richer !

Graphene crystallographically aligned on boron nitride flakes is found to exhibit second generation Dirac points and reversal of Hall effect. Cloning of Dirac points is observed under high magnetic field leading to third generation Dirac points. The results pave way for controlling the electronic structure of graphene in superlattice configurations.

Thursday, May 16, 2013

Photoresponsive graphene

It is known that graphene has no band gap and hence does not exhibit photoreponse. However, by band structure engineering, one can open up the band gap. In a recent report, researchers have obtained a high photoresponsivity of around 8 A/W in monolayer graphene by creating electron trapping centres. The results pave way for optoelectronic applications of graphene.

Wednesday, May 1, 2013

Mie scattering analog in graphene

It is proved theoretically that Dirac electron wave in graphene can be manipulated similar to Mie scattering of light on small particles. It is realized by using circular gating region in graphene which acts as a quantum dot.

Negative differential conductance in graphene transistors

Graphene's low density of states have been utilised for resonant tunneling through a boron nitride film and negative differential conductance in graphene transistors. The device is comprised of a few layer thick boron nitride layer sandwiched between graphene layers. The few atomic thick device promises to have ultrafast transient times.