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 Perovskite-silicon solar cell research collaboration hits 25.2% efficiency
15.06.2018 | Helmholtz-Zentrum Berlin für Materialien und Energie GmbH

nachricht Second heat source optimises heat pump system
12.06.2018 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH

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: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

Im Focus: Photoexcited graphene puzzle solved

A boost for graphene-based light detectors

Light detection and control lies at the heart of many modern device applications, such as smartphone cameras. Using graphene as a light-sensitive material for...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Carbon nanotube optics provide optical-based quantum cryptography and quantum computing

19.06.2018 | Physics and Astronomy

How to track and trace a protein: Nanosensors monitor intracellular deliveries

19.06.2018 | Life Sciences

New material for splitting water

19.06.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>