Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New 'tunable' semiconductors will allow better detectors, solar cells

14.04.2014

One of the great problems in physics is the detection of electromagnetic radiation – that is, light – which lies outside the small range of wavelengths that the human eye can see. Think X-rays, for example, or radio waves.

Now, researchers have discovered a way to use existing semiconductors to detect a far wider range of light than is now possible, well into the infrared range. The team hopes to use the technology in detectors, obviously, but also in improved solar cells that could absorb infrared light as well as the sun's visible rays.

"This technology will also allow dual or multiband detectors to be developed, which could be used to reduce false positives in identifying, for example, toxic gases," said Unil Perera, a Regents' Professor of Physics at Georgia State University. Perera leads the Optoelectronics Research Laboratory, where fellow author and postdoctoral fellow Yan-Feng Lao is also a member. The research team also included scientists from the University of Leeds in England and Shanghai Jiao Tong University in China.

To understand the team's breakthrough, it's important to understand how semiconductors work. Basically, a semiconductor is exactly what its name implies – a material that will conduct an electromagnetic current, but not always. An external energy source must be used to get those electrons moving.

But infrared light doesn't carry a lot of energy, and won't cause many semiconductors to react. And without a reaction, there's nothing to detect.

Until now, the only solution would have been to find a semiconductor material that would respond to long-wavelength, low-energy light like the infrared spectrum.

But instead, the researchers worked around the problem by adding another light source to their device. The extra light source primes the semiconductor with energy, like running hot water over a jar lid to loosen it. When a low-energy, long-wavelength beam comes along, it pushes the material over the top, causing a detectable reaction.

The new and improved device can detect wavelengths up to at least the 55 micrometer range, whereas before the same detector could only see wavelengths of about 4 micrometers. The team has run simulations showing that a refined version of the device could detect wavelengths up to 100 micrometers long.

Edmund Linfield, professor of terahertz electronics at the University of Leeds, whose team built the patterned semiconductors used in the new technique, said, "This is a really exciting breakthrough and opens up the opportunity to explore a wide range of new device concepts including more efficient photovoltaics and photodetectors."

Perera and Lao have filed a U.S. patent application for their detector design.

###

"Tunable hot-carrier photodetection beyond the band-gap spectral limit" by Yan-Feng Lao, A.G. Unil Perera, L.H. Li, S.P. Khanna, E.H. Linfield and H.C. Liu is in the May issue of Nature Photonics.

The work was supported by the U.S. Army Research Office, the U.S. National Science Foundation, the UK Engineering and Physical Sciences Research Council, and the European Research Council Advanced Grant "TOSCA."

Ann Claycombe | Eurek Alert!

Further reports about: Nature Photonics Physics Science detector reaction semiconductors spectrum wavelengths

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

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>