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The University of Manchester - Tense Graphene joins forces with Gold nano-antennas

DCN Corp® - 'Tense' Graphene join forces with gold nano-antennas, the future of nano semiconductors.  Credit - The University of Manchester (UoM), Freie Universitat Berlin and Imperial College London (ICL)

As researched by University of Manchester (UoM) scientists, the claimed 'wonder material' (Graphene) is being employed to investigate how light interacts with nano-antennas - potentially increasing the efficiency of solar cells and photo detectors

Publishing in Nano Letters [1] and Physica Status Solidi Rapid Research Letters [2] - a team led by Dr Aravind Vijayaraghavan in collaboration with Professor Stephanie Reich (Freie Universitat Berlin) and Professor Stefan Maier (Imperial College London, ICL) - have demonstrated that Graphene can be employed to investigate how light interacts with Gold (Au) nano-structures of different shapes, sizes and geometry.

The light interaction - typically known as Surface Plasmon Resonance (SPR) - is the same phenomenon which gives colour to the gothic stained glass rose window of Notre-Dame de Paris, France.  For example, when light shines on a nano-metallic particle smaller than the wavelength of the light, then the electrons in the particle start to move back and forth along with the light wave.  Effectively this causes an increase in the electric field at the surface of the particle.

Consequently when two such particles are brought close to each other, the oscillating electrons in the two particles interact with each other, thus, forming a much higher electric field between the two particles, resulting in a coupling between the two particles.  Please Note a negative counter-effect of such a phenomenon is known as SPR "hot-spots".  To that effect UK/international research has burgeoned - trying to ensure that the observation and magnitude of the coupling and resulting electric field is maintained in a consistent/reproducible manner.

Dr Vijayaraghavan's team and collaborators have shown that Graphene can be placed on top of such coupled Au antennas of different shapes, and after performing Raman spectroscopy on the Graphene it has enabled inhabitant of the coupled plasmonic system.

Dr Vijayaraghavan continues to state: "When a sheet of Graphene, just one atom thick, is placed on top of two gold particles next to each other, the Graphene bends around the particles and gets stretched in the gap between the particles.  When light falls on the Graphene, it is scattered to different extents from the strained and unstrained parts of the Graphene.

Fortunately, the strained part of the Graphene also lies in the same region as the plasonic electric field - in the cavity in between the two dots.  This allows use to compare the amount of light scattered by the plasmonic cavity and the surrounding region, and derive a quantity for the enhancement from the plasmonic antenna cavity.

The light scattered from the strained Graphene can be 1000 times brighter than the light from the surrounding Graphene."  Original article available here

The above collaboration clearly demonstrates the potential gained from even fabrication of metallic nano particles - especially in the emerging sector of nano semiconductors.  Therefore, in seeking to competitively supersede - if you and/or your colleagues are interested in making the above concept reality - please ensure to contact the company as soon as practicably possible.

[1] Heeg, S., Oikonomou, A., Fernandez-Garcia, R., Maier, S.A., Vijayaraghavan, A. and Reich, S. Strained graphene as a local probe for plasmon-enhanced Raman scattering by gold nanostructures. Physica Status Solidi RRL

[2] Heeg, S., Fernandez-Garcia, R., Oikonomou, A., Schedin, F., Narula, R., Maier, S.A., Vijayaraghavan and Reich, S. Polarised plasmonic enhancement by Au nano structures probed through Raman scattering of suspended graphene. Nano Letters