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Sunday, June 16, 2013

Dual gated bilayer graphene shows photothermal response

Graphene is seen as a potential candidate for photodetection applications. Now, the researchers have studied dual gated bilayer graphene to observe the gating effect on its photothermal response. They have found a significant role of hot electron thermal relaxation in defining the photovoltaic response of graphene.

http://prl.aps.org/abstract/PRL/v110/i24/e247402

Multilayer graphene shows temperature dependence of far-infrared response

Graphene possesses miracle optical properties with exhibition of broadband transmission irrespective of the wavelength of light. However, researchers have found a temperature dependence of far-infrared response of epitaxial multilayer graphene. The results are vital for graphene based devices.

http://apl.aip.org/resource/1/applab/v102/i23/p231906_s1

Flexible graphene radio frequency devices

The mechanical strength of graphene allows one to fabricate flexible devices. The researchers have now demonstrated flexible graphene radio frequency devices with cut off frequencies as high as 10 GHz with a temperature stability upto 400 K. 

http://apl.aip.org/resource/1/applab/v102/i23/p233102_s1

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.

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature12187.html

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.

http://www.nature.com/ncomms/journal/v4/n5/abs/ncomms2830.html

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.

http://prb.aps.org/abstract/PRB/v87/i15/e155409

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.

http://www.nature.com/ncomms/journal/v4/n4/abs/ncomms2817.html?WT.ec_id=NCOMMS-20130430