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 Could off-grid electricity systems accelerate energy access?
26.04.2016 | International Institute for Applied Systems Analysis (IIASA)

nachricht Test of the no-harm-criteria of additives
19.04.2016 | Oel-Waerme-Institut 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: Tiny microbots that can clean up water

Researchers from the Max Planck Institute Stuttgart have developed self-propelled tiny ‘microbots’ that can remove lead or organic pollution from contaminated water.

Working with colleagues in Barcelona and Singapore, Samuel Sánchez’s group used graphene oxide to make their microscale motors, which are able to adsorb lead...

Im Focus: ORNL researchers discover new state of water molecule

Neutron scattering and computational modeling have revealed unique and unexpected behavior of water molecules under extreme confinement that is unmatched by any known gas, liquid or solid states.

In a paper published in Physical Review Letters, researchers at the Department of Energy's Oak Ridge National Laboratory describe a new tunneling state of...

Im Focus: Bionic Lightweight Design researchers of the Alfred Wegener Institute at Hannover Messe 2016

Honeycomb structures as the basic building block for industrial applications presented using holo pyramid

Researchers of the Alfred Wegener Institute (AWI) will introduce their latest developments in the field of bionic lightweight design at Hannover Messe from 25...

Im Focus: New world record for fullerene-free polymer solar cells

Polymer solar cells can be even cheaper and more reliable thanks to a breakthrough by scientists at Linköping University and the Chinese Academy of Sciences (CAS). This work is about avoiding costly and unstable fullerenes.

Polymer solar cells can be even cheaper and more reliable thanks to a breakthrough by scientists at Linköping University and the Chinese Academy of Sciences...

Im Focus: Ultra-thin glass is up and coming

As one of the leading R&D partners in the development of surface technologies and organic electronics, the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP will be exhibiting its recent achievements in vacuum coating of ultra-thin glass at SVC TechCon 2016 (Booth 846), taking place in Indianapolis / USA from May 9 – 13.

Fraunhofer FEP is an experienced partner for technological developments, known for testing the limits of new materials and for optimization of those materials...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

The “AC21 International Forum 2016” is About to Begin

27.04.2016 | Event News

Soft switching combines efficiency and improved electro-magnetic compatibility

15.04.2016 | Event News

Grid-Supportive Buildings Give Boost to Renewable Energy Integration

12.04.2016 | Event News

 
Latest News

Winds a quarter the speed of light spotted leaving mysterious binary systems

29.04.2016 | Physics and Astronomy

Fiber optic biosensor-integrated microfluidic chip to detect glucose levels

29.04.2016 | Health and Medicine

A cell senses its own curves: New research from the MBL Whitman Center

29.04.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>