Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > A light bright and tiny: NIST scientists build a better nanoscale LED: New design overcomes long-standing LED efficiency problem -- and can transform into a laser to boot

The fin LED pixel design includes the glowing zinc oxide fin (purple), isolating dielectric material (green), and metal contact (yellow atop green).

CREDIT
B. Nikoobakht / N. Hanacek, NIST
The fin LED pixel design includes the glowing zinc oxide fin (purple), isolating dielectric material (green), and metal contact (yellow atop green). CREDIT B. Nikoobakht / N. Hanacek, NIST

Abstract:
A new design for light-emitting diodes (LEDs) developed by a team including scientists at the National Institute of Standards and Technology (NIST) may hold the key to overcoming a long-standing limitation in the light sources' efficiency. The concept, demonstrated with microscopic LEDs in the lab, achieves a dramatic increase in brightness as well as the ability to create laser light -- all characteristics that could make it valuable in a range of large-scale and miniaturized applications.

A light bright and tiny: NIST scientists build a better nanoscale LED: New design overcomes long-standing LED efficiency problem -- and can transform into a laser to boot

Gaithersburg, MD | Posted on August 14th, 2020

The team, which also includes scientists from the University of Maryland, Rensselaer Polytechnic Institute and the IBM Thomas J. Watson Research Center, detailed its work in a paper published today in the peer-reviewed journal Science Advances. Their device shows an increase in brightness of 100 to 1,000 times over conventional tiny, submicron-sized LED designs.

"It's a new architecture for making LEDs," said NIST's Babak Nikoobakht, who conceived the new design. "We use the same materials as in conventional LEDs. The difference in ours is their shape."

LEDs have existed for decades, but the development of bright LEDs won a Nobel prize and ushered in a new era of lighting. However, even modern LEDs have a limitation that frustrates their designers. Up to a point, feeding an LED more electricity makes it shine more brightly, but soon the brightness drops off, making the LED highly inefficient. Called "efficiency droop" by the industry, the issue stands in the way of LEDs being used in a number of promising applications, from communications technology to killing viruses.

While their novel LED design overcomes efficiency droop, the researchers did not initially set out to solve this problem. Their main goal was to create a microscopic LED for use in very small applications, such as the lab-on-a-chip technology that scientists at NIST and elsewhere are pursuing.

The team experimented with a whole new design for the part of the LED that shines: Unlike the flat, planar design used in conventional LEDs, the researchers built a light source out of long, thin zinc oxide strands they refer to as fins. (Long and thin are relative terms: Each fin is only about 5 micrometers in length, stretching about a tenth of the way across an average human hair's breadth.) Their fin array looks like a tiny comb that can extend to areas as large as 1 centimeter or more.

"We saw an opportunity in fins, as I thought their elongated shape and large side facets might be able to receive more electrical current," Nikoobakht said. "At first we just wanted to measure how much the new design could take. We started increasing the current and figured we'd drive it until it burned out, but it just kept getting brighter."

Their novel design shone brilliantly in wavelengths straddling the border between violet and ultraviolet, generating about 100 to 1,000 times as much power as typical tiny LEDs do. Nikoobakht characterizes the result as a significant fundamental discovery.

"A typical LED of less than a square micrometer in area shines with about 22 nanowatts of power, but this one can produce up to 20 microwatts," he said. "It suggests the design can overcome efficiency droop in LEDs for making brighter light sources."

"It's one of the most efficient solutions I have seen," said Grigory Simin, a professor of electrical engineering at the University of South Carolina who was not involved in the project. "The community has been working for years to improve LED efficiency, and other approaches often have technical issues when applied to submicrometer wavelength LEDs. This approach does the job well."

The team made another surprising discovery as they increased the current. While the LED shone in a range of wavelengths at first, its comparatively broad emission eventually narrowed to two wavelengths of intense violet color. The explanation grew clear: Their tiny LED had become a tiny laser.

"Converting an LED into a laser takes a large effort. It usually requires coupling a LED to a resonance cavity that lets the light bounce around to make a laser," Nikoobakht said. "It appears that the fin design can do the whole job on its own, without needing to add another cavity."

A tiny laser would be critical for chip-scale applications not only for chemical sensing, but also in next-generation hand-held communications products, high-definition displays and disinfection.

"It's got a lot of potential for being an important building block," Nikoobakht said. "While this isn't the smallest laser people have made, it's a very bright one. The absence of efficiency droop could make it useful."

###

The research was supported in part by the U.S. Army Cooperative Research Agreement.

####

For more information, please click here

Contacts:
Chad Boutin


@NIST

Copyright © National Institute of Standards and Technology (NIST)

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Intelligent optical chip to improve telecommunications: An INRS team uses autonomous learning approaches for optical waveform generators to boost optical signal processing functionalities for current and future telecom applications October 15th, 2021

Using quantum Parrondo’s random walks for encryption: Asst Prof Kang Hao Cheong and his research team from SUTD have set out to apply concepts from quantum Parrondo’s paradox in search of a working protocol for semiclassical encryption October 15th, 2021

Cellular environments shape molecular architecture: Researchers glean a more complete picture of a structure called the nuclear pore complex by studying it directly inside cells October 15th, 2021

How to program DNA robots to poke and prod cell membranes: A discovery of how to build little blocks out of DNA and get them to stick to lipids has implications for biosensing and mRNA vaccines October 15th, 2021

Laboratories

Unprecedented view of a single catalyst nanoparticle at work: X-rays reveal compositional changes on active surface under reaction conditions October 1st, 2021

A simple way to get complex semiconductors to assemble themselves: Much like crystallizing rock candy from sugar syrup, the new method grows 2D perovskites precisely layered with other 2D materials to produce crystals with a wide range of electronic properties September 17th, 2021

Scientists demonstrate pathway to forerunner of nanotubes that could lead to widespread industrial fabrication September 17th, 2021

Patterning silicon at the one nanometer scale: Scientists engineer materials’ electrical and optical properties with plasmon engineering August 13th, 2021

Verizon and Zurich Instruments join Q-NEXT national quantum science center August 6th, 2021

Display technology/LEDs/SS Lighting/OLEDs

New substance classes for nanomaterials: Nano spheres and diamond slivers made of silicon and germanium: Potential applications as nano semiconductor materials September 10th, 2021

Controlling chaos in liquid crystals, gaining precision in autonomous technologies August 6th, 2021

Govt.-Legislation/Regulation/Funding/Policy

Molecular Sciences Software Institute receives $15 million grant from National Science Foundation October 15th, 2021

Scientists discover spin polarization induced by shear flow October 1st, 2021

UTA project aims to extend life of concrete, cement by adding nanoscale wood fibers: Wood fibers key to sustainable concrete, cement September 24th, 2021

A simple way to get complex semiconductors to assemble themselves: Much like crystallizing rock candy from sugar syrup, the new method grows 2D perovskites precisely layered with other 2D materials to produce crystals with a wide range of electronic properties September 17th, 2021

Possible Futures

Using quantum Parrondo’s random walks for encryption: Asst Prof Kang Hao Cheong and his research team from SUTD have set out to apply concepts from quantum Parrondo’s paradox in search of a working protocol for semiclassical encryption October 15th, 2021

Cellular environments shape molecular architecture: Researchers glean a more complete picture of a structure called the nuclear pore complex by studying it directly inside cells October 15th, 2021

How to program DNA robots to poke and prod cell membranes: A discovery of how to build little blocks out of DNA and get them to stick to lipids has implications for biosensing and mRNA vaccines October 15th, 2021

Molecular Sciences Software Institute receives $15 million grant from National Science Foundation October 15th, 2021

Optical computing/Photonic computing

Photon-pair source with pump rejection filter fabricated on single CMOS chip: New integrated source provides critical component for chip-based quantum photonic systems October 15th, 2021

Ultrafast magnetism: heating magnets, freezing time: This study on Gadolinium is completing a series of experiments on Nickel, Iron-Nickel Alloys: The results are useful for developing ultrafast data storage devices October 15th, 2021

Nanoscale lattices flow from 3D printer: Rice University engineers create nanostructures of glass and crystal for electronics, photonics October 15th, 2021

MXene-GaN van der Waals metal-semiconductor junctions for high performance photodetection September 24th, 2021

Discoveries

Intelligent optical chip to improve telecommunications: An INRS team uses autonomous learning approaches for optical waveform generators to boost optical signal processing functionalities for current and future telecom applications October 15th, 2021

Using quantum Parrondo’s random walks for encryption: Asst Prof Kang Hao Cheong and his research team from SUTD have set out to apply concepts from quantum Parrondo’s paradox in search of a working protocol for semiclassical encryption October 15th, 2021

Cellular environments shape molecular architecture: Researchers glean a more complete picture of a structure called the nuclear pore complex by studying it directly inside cells October 15th, 2021

How to program DNA robots to poke and prod cell membranes: A discovery of how to build little blocks out of DNA and get them to stick to lipids has implications for biosensing and mRNA vaccines October 15th, 2021

Announcements

Using quantum Parrondo’s random walks for encryption: Asst Prof Kang Hao Cheong and his research team from SUTD have set out to apply concepts from quantum Parrondo’s paradox in search of a working protocol for semiclassical encryption October 15th, 2021

Cellular environments shape molecular architecture: Researchers glean a more complete picture of a structure called the nuclear pore complex by studying it directly inside cells October 15th, 2021

How to program DNA robots to poke and prod cell membranes: A discovery of how to build little blocks out of DNA and get them to stick to lipids has implications for biosensing and mRNA vaccines October 15th, 2021

Molecular Sciences Software Institute receives $15 million grant from National Science Foundation October 15th, 2021

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters

Intelligent optical chip to improve telecommunications: An INRS team uses autonomous learning approaches for optical waveform generators to boost optical signal processing functionalities for current and future telecom applications October 15th, 2021

Using quantum Parrondo’s random walks for encryption: Asst Prof Kang Hao Cheong and his research team from SUTD have set out to apply concepts from quantum Parrondo’s paradox in search of a working protocol for semiclassical encryption October 15th, 2021

Cellular environments shape molecular architecture: Researchers glean a more complete picture of a structure called the nuclear pore complex by studying it directly inside cells October 15th, 2021

How to program DNA robots to poke and prod cell membranes: A discovery of how to build little blocks out of DNA and get them to stick to lipids has implications for biosensing and mRNA vaccines October 15th, 2021

Military

Scientists demonstrate pathway to forerunner of nanotubes that could lead to widespread industrial fabrication September 17th, 2021

Putting a new theory of many-particle quantum systems to the test: Experiments show that generalized hydrodynamics accurately simulates an out-of-equilibrium quantum system September 3rd, 2021

NIST’s quantum crystal could be a new dark matter sensor Peer-Reviewed Publication August 6th, 2021

UVA Engineering researchers join quest to demonstrate photonic systems-on-chip: Future applications include faster, more efficient data centers and next-generation millimeter-wave wireless communication July 30th, 2021

Photonics/Optics/Lasers

Photon-pair source with pump rejection filter fabricated on single CMOS chip: New integrated source provides critical component for chip-based quantum photonic systems October 15th, 2021

Ultrafast magnetism: heating magnets, freezing time: This study on Gadolinium is completing a series of experiments on Nickel, Iron-Nickel Alloys: The results are useful for developing ultrafast data storage devices October 15th, 2021

Nanoscale lattices flow from 3D printer: Rice University engineers create nanostructures of glass and crystal for electronics, photonics October 15th, 2021

MXene-GaN van der Waals metal-semiconductor junctions for high performance photodetection September 24th, 2021

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project