Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Photonics: A more sensitive device

28.03.2011
Electron resonances could greatly enhance the response of the photodetectors critical to the operation of optical chips

Optical chips are the latest innovation in silicon technology with the potential to revolutionize telecommunications. Their operation relies on several key components, including light-emitting devices, waveguides and photodetectors. Engineers are looking for ways to miniaturize these components without sacrificing the data-processing speed of the integrated optical chips.

Patrick Guo-Qiang Lo and co-workers at the A*STAR Institute of Microelectronics[1] have now fabricated a highly sensitive photodetector by exploiting the enhancement effects of electron resonances that occur at metal contacts.

Surface plasmon polaritons—the collective movements of electrons at the surface of metals—are known to enhance and focus electromagnetic waves in their vicinity. The plasmon effect has been studied extensively for its ability to enhance the performance of optical devices, but in this study the researchers applied the phenomenon to improved the sensitivity, and hence speed, of semiconductor detectors.

Photodetectors on a silicon chip are generally designed to pick up light arriving through silicon waveguides. The light travelling through the silicon waveguides is detected by germanium, another semiconductor, which is grown directly on top of the silicon structure. However, the sensitivity of the germanium detector needs to be enhanced considerably in order to increase the speed and reduce the footprint of the photodetector further.

Plasmonic resonances can easily enhance the sensitivity of this light detection. The researchers introduced plasmons by adding thin aluminum contacts on top of the device (pictured). The plasmonic effects in the metal films channel considerably more light from the silicon waveguide into the photodetector, with important implications for device performance. “The enhanced photodetection enables the use of smaller devices, which in turn means that the device speed can be increased considerably,” explains Lo.

The researchers demonstrate detection speeds of 37.6 picoseconds or faster, corresponding to a data transmission speed of 11.4 gigahertz—several orders of magnitude faster than that achievable by current broadband connections.

At the same time, these speeds still lag behind the full potential of these detectors. One of the reasons, says Lo, is loss that arises from the plasmonic resonances, which absorb some of the light and therefore reduce the amount of light that arrives at the detector. “The response of the detector is lower than what we expected from our design,” says Lo. “Enhancing the plasmonic properties of the detector, for example through the design of different geometries, could alleviate such problems and enable a further miniaturization of photodetectors on silicon chips.”

The A*STAR-affiliated researchers contributing to this research are from the Institute of Microelectronics

Journal information

[1] Ren, F.-F. et al. Surface plasmon enhanced responsivity in a waveguided germanium metal-semiconductor-metal photodetector. Applied Physics Letters 97, 091102 (2010).

Lee Swee Heng | Research asia research news
Further information:
http://www.research.a-star.edu.sg/research/6293
http://www.researchsea.com

More articles from Power and Electrical Engineering:

nachricht How protons move through a fuel cell
22.06.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

nachricht Fraunhofer IZFP acquires lucrative EU project for increasing nuclear power plant safety
21.06.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Study shines light on brain cells that coordinate movement

26.06.2017 | Life Sciences

Smooth propagation of spin waves using gold

26.06.2017 | Physics and Astronomy

Switchable DNA mini-machines store information

26.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>