Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Graphene pushes the speed limit of light-to-electricity conversion

15.04.2015

Researchers from ICFO, MIT and UC Riverside have been able to develop a graphene-based photodetector capable of converting absorbed light into an electrical voltage at ultrafast timescales

The efficient conversion of light into electricity plays a crucial role in many technologies, ranging from cameras to solar cells.


This is an illustration of ultrafast photovoltage creation after light absorption at the interface of two graphene areas with different Fermi energy.

Credit

ICFO/Achim Woessner (Image courtesy Achim Woessner)

It also forms an essential step in data communication applications, since it allows for information carried by light to be converted into electrical information that can be processed in electrical circuits.

Graphene is an excellent material for ultrafast conversion of light to electrical signals, but so far it was not known how fast graphene responds to ultrashort flashes of light.

ICFO researchers Klaas-Jan Tielrooij, Lukasz Piatkowski, Mathieu Massicotte and Achim Woessner led by ICFO Prof. Frank Koppens and ICREA Prof. at ICFO Niek van Hulst, in collaboration with scientists from the research group led by Pablo Jarillo-Herrero at MIT and the research group led by Jeanie Lau at UC Riverside, have now demonstrated that a graphene-based photodetector converts absorbed light into an electrical voltage at an extremely high speed.

The study, entitled "Generation of photovoltage in graphene on a femtosecond timescale through efficient carrier heating", has recently been published in Nature Nanotechnology.

The new device that the researchers developed is capable of converting light into electricity in less than 50 femtoseconds (a twentieth of a millionth of a millionth of a second). To do this, the researchers used a combination of ultrafast pulse-shaped laser excitation and highly sensitive electrical readout.

As Klaas-Jan Tielrooij comments, "the experiment uniquely combined the ultrafast pulse shaping expertise obtained from single molecule ultrafast photonics with the expertise in graphene electronics. Facilitated by graphene's nonlinear photo-thermoelectric response, these elements enabled the observation of femtosecond photodetection response times."

The ultrafast creation of a photovoltage in graphene is possible due to the extremely fast and efficient interaction between all conduction band carriers in graphene. This interaction leads to a rapid creation of an electron distribution with an elevated electron temperature.

Thus, the energy absorbed from light is efficiently and rapidly converted into electron heat. Next, the electron heat is converted into a voltage at the interface of two graphene regions with different doping. This photo-thermoelectric effect turns out to occur almost instantaneously, thus enabling the ultrafast conversion of absorbed light into electrical signals. As Prof. van Hulst states, "it is amazing how graphene allows direct non-linear detecting of ultrafast femtosecond (fs) pulses".

The results obtained from the findings of this work, which has been partially funded by the EC Graphene Flagship, open a new pathway towards ultra-fast optoelectronic conversion. As Prof. Koppens comments, "Graphene photodetectors keep showing fascinating performances addressing a wide range of applications".

###

REFERENCE

Generation of photovoltage in graphene on a femtosecond timescale through efficient carrier heating, Nature Nanotechnology.
K. J. Tielrooij, L. Piatkowski, M. Massicotte, A. Woessner, Q. Ma, Y. Lee, K.S. Myhro, C.N. Lau, P. Jarillo Herrero, N. van Hulst and F. H. L. Koppens.
DOI: 10.1038/nnano.2015.54

FUNDING INFO

This work was funded by the E.C. under Graphene Flagship, as well as an NWO Rubicon fellowship, an ICFO-Cofund fellowship, The Fundacio Cellex Barcelona, the ERC and the MIT MISTI-Spain program.

ABOUT ICFO

ICFO-The Institute of Photonic Sciences was created in 2002 by the government of Catalonia and the Technical University of Catalonia as a centre of research excellence devoted to the science and technologies of light with a triple mission: to conduct frontier research, train the next generation of scientists, and provide knowledge and technology transfer. Today, it is one of the top research centres worldwide in its category as measured by international rankings.

Research at ICFO targets the forefront of science and technology based on light with programs directed at applications in Health, Renewable Energies, Information Technologies, Security and Industrial processes, among others. The institute hosts 300 professionals based in a dedicated building situated in the Mediterranean Technology Park in the metropolitan area of Barcelona.

ICFO participates in a large number of projects and international networks of excellence and is host to the NEST program which is financed by Fundación Privada Cellex Barcelona. Ground-breaking research in graphene is being carried out at ICFO and through key collaborative research partnerships such as the FET Graphene Flagship. Prof Frank Koppens is the co-leader of the Optoelectronics work package within the Flagship program.

Media Contact

Alina Hirschmann
alina.hirschmann@icfo.es
34-935-542-246

http://www.icfo.es 

Alina Hirschmann | EurekAlert!

More articles from Physics and Astronomy:

nachricht Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State

nachricht What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>