Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Biomimetic photodetector 'sees' in color

26.08.2014

Rice lab uses CMOS-compatible aluminum for on-chip color detection

Rice University researchers have created a CMOS-compatible, biomimetic color photodetector that directly responds to red, green and blue light in much the same way the human eye does.


Researchers at Rice University's Laboratory for Nanophotonics have demonstrated a method for designing imaging sensors by integrating light amplifiers and color filters directly into pixels.

Credit: Bob Zheng/Rice University

The new device was created by researchers at Rice's Laboratory for Nanophotonics (LANP) and is described online in a new study in the journal Advanced Materials. It uses an aluminum grating that can be added to silicon photodetectors with the silicon microchip industry's mainstay technology, "complementary metal-oxide semiconductor," or CMOS.

Conventional photodetectors convert light into electrical signals but have no inherent color-sensitivity. To capture color images, photodetector makers must add color filters that can separate a scene into red, green and blue color components. This color filtering is commonly done using off-chip dielectric or dye color filters, which degrade under exposure to sunlight and can also be difficult to align with imaging sensors.

"Today's color filtering mechanisms often involve materials that are not CMOS-compatible, but this new approach has advantages beyond on-chip integration," said LANP Director Naomi Halas, the lead scientist on the study. "It's also more compact and simple and more closely mimics the way living organisms 'see' colors.

Biomimicry was no accident. The color photodetector resulted from a $6 million research program funded by the Office of Naval Research that aimed to mimic cephalopod skin using "metamaterials," compounds that blur the line between material and machine.

Cephalopods like octopus and squid are masters of camouflage, but they are also color-blind. Halas said the "squid skin" research team, which includes marine biologists Roger Hanlon of the Marine Biological Laboratory in Woods Hole, Mass., and Thomas Cronin of the University of Maryland, Baltimore County, suspect that cephalopods may detect color directly through their skin.

Based on that hypothesis, LANP graduate student Bob Zheng, the lead author of the new Advanced Materials study, set out to design a photonic system that could detect colored light.

"Bob has created a biomimetic detector that emulates what we are hypothesizing the squid skin 'sees,'" Halas said. "This is a great example of the serendipity that can occur in the lab. In searching for an answer to a specific research question, Bob has created a device that is far more practical and generally applicable."

Zheng's color photodetector uses a combination of band engineering and plasmonic gratings, comb-like aluminum structures with rows of parallel slits. Using electron-beam evaporation, which is a common technique in CMOS processing, Zheng deposited a thin layer of aluminum onto a silicon photodetector topped with an ultrathin oxide coating.

Color selection is performed by utilizing interference effects between the plasmonic grating and the photodetector's surface. By carefully tuning the oxide thickness and the width and spacing of the slits, Zheng was able to preferentially direct different colors into the silicon photodetector or reflect it back into free space.

The metallic nanostructures use surface plasmons -- waves of electrons that flow like a fluid across metal surfaces. Light of a specific wavelength can excite a plasmon, and LANP researchers often create devices where plasmons interact, sometimes with dramatic effects.

"With plasmonic gratings, not only do you get color tunability, you can also enhance near fields," Zheng said. "The near-field interaction increases the absorption cross section, which means that the grating sort of acts as its own lens. You get this funneling of light into a concentrated area.

"Not only are we using the photodetector as an amplifier, we're also using the plasmonic color filter as a way to increase the amount of light that goes into the detector," he said.

###

Co-authors include Rice graduate student Yumin Wang and Peter Nordlander, professor of physics and astronomy at Rice.

This release can be found online at news.rice.edu.

Follow Rice News and Media Relations on Twitter @RiceUNews.

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,920 undergraduates and 2,567 graduate students, Rice's undergraduate student-to-faculty ratio is just over 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is highly ranked for best quality of life by the Princeton Review and for best value among private universities by Kiplinger's Personal Finance.

David Ruth | Eurek Alert!
Further information:
http://www.rice.edu

Further reports about: Biomimetic CMOS detector effects photodetector photodetectors skin

More articles from Power and Electrical Engineering:

nachricht Transforming waste heat directly into electricity
03.05.2016 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH

nachricht Did you know that Heraeus PID lamps have been used in the measurement of air quality at the London airport?
02.05.2016 | Heraeus Noblelight 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: Nuclear Pores Captured on Film

Using an ultra fast-scanning atomic force microscope, a team of researchers from the University of Basel has filmed “living” nuclear pore complexes at work for the first time. Nuclear pores are molecular machines that control the traffic entering or exiting the cell nucleus. In their article published in Nature Nanotechnology, the researchers explain how the passage of unwanted molecules is prevented by rapidly moving molecular “tentacles” inside the pore.

Using high-speed AFM, Roderick Lim, Argovia Professor at the Biozentrum and the Swiss Nanoscience Institute of the University of Basel, has not only directly...

Im Focus: 2+1 is Not Always 3 - In the microworld unity is not always strength

If a person pushes a broken-down car alone, there is a certain effect. If another person helps, the result is the sum of their efforts. If two micro-particles are pushing another microparticle, however, the resulting effect may not necessarily be the sum their efforts. A recent study published in Nature Communications, measured this odd effect that scientists call “many body.”

In the microscopic world, where the modern miniaturized machines at the new frontiers of technology operate, as long as we are in the presence of two...

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...

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

Expanding tropics pushing high altitude clouds towards poles, NASA study finds

06.05.2016 | Earth Sciences

IU-led study reveals new insights into light color sensing and transfer of genetic traits

06.05.2016 | Life Sciences

Thievish hoverfly steals prey from carnivorous sundews

06.05.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>