Light sensor breakthrough could enhance digital cameras

Jun 18, 2009

New research by a team of University of Toronto scientists could lead to substantial advancements in the performance of a variety of electronic devices including digital cameras.

Researchers created a light sensor - like a pixel in a - that benefits from a phenomenon known as multi-exciton generation (MEG). Until now, no group had collected an electrical current from a device that takes advantage of MEG.

"Digital cameras are now universal, but they suffer from a major limitation: they take poor pictures under dim light. One reason for this is that the image sensor chips inside cameras collect, at most, one electron's worth of current for every photon (particle of light) that strikes the pixel," says Ted Sargent, professor in U of T's Department of Electrical and Computer Engineering. "Instead generating multiple excitons per photon could ultimately lead to better low-light pictures."

In and digital cameras, particles of light - known as - are absorbed in a semiconductor, such a silicon, and generate excited electrons, known as excitons. The semiconductor chip then measures a current that flows as a result. Normally, each photon is converted into at most one exciton. This lowers the efficiency of solar cells and it limits the sensitivity of digital cameras. When a scene is dimly lit, small portable cameras like those in laptops suffer from noise and grainy images as a result of the small number excitons.

"Multi-exciton generation breaks the conventional rules that bind traditional semiconductor devices," says Sargent. "This finding shows that it's more than a fascinating concept: the tangible benefits of multiple excitons can be seen in a light sensor's measured current."

Source: University of Toronto (news : web)

Explore further: Greater safety and security at Europe's train stations

add to favorites email to friend print save as pdf

Related Stories

Greatly Improved Solar Cells

Apr 21, 2004

Victor Klimov and Richard Schaller at Los Alamos National Laboratory have enhanced the phenomenon called "impact ionization," which can significantly improve the efficiency of the conversion of solar energy to ...

Researchers send 'heavy photons' over world-record distances

Jun 21, 2005

Unsurpassed exciton distances, lifetimes may lead to new form of optical communication When light hits a semiconductor material and is absorbed, its photons can become "excitons," sometimes referred to as "heavy photons" ...

Excitons play peek-a-boo on carbon nanotubes

Jun 07, 2007

In the quantum world, photons and electrons dance, bump and carry out transactions that govern everything we see in the world around us. In this week's issue of Science, French and U.S. scientists describe a new technique ...

Substantial improvement in essential cheap solar cell process

Mar 20, 2008

A cheap alternative to silicon solar cells can be found in dye-sensitised solar cells. This type of cell imitates the natural conversion of sunlight into energy by, for instance, plants and light-sensitive bacteria. Annemarie ...

Recommended for you

Greater safety and security at Europe's train stations

Sep 01, 2014

When a suspicious individual fleas on a bus or by train, then things usually get tough for the police. This is because the security systems of the various transportation companies and security services are ...

Fingerprints for freight items

Sep 01, 2014

Security is a top priority in air freight logistics but screening procedures can be very time consuming and costly. Fraunhofer researchers intend to boost efficiency with a new approach to digital logistics, ...

On the way to a safe and secure smart home

Sep 01, 2014

A growing number of household operations can be managed via the Internet. Today's "Smart Home" promises efficient building management. But often the systems are not secure and can only be retrofitted at great ...

DIY glove-based tutor indicates muscle-memory potential

Aug 31, 2014

A senior editor at IEEE Spectrum worked on a DIY project that enabled his 11-year-old son to improve his touch typing by use of a vibrating glove. His son was already "pretty quick on the keyboard," said ...

User comments : 0