Featured Research

from universities, journals, and other organizations

Novel Nano-etched Cavity Makes LEDs 7 Times Brighter

Date:
July 23, 2006
Source:
National Institute of Standards and Technology
Summary:
Researchers at NIST have made semiconductor light-emitting diodes (LEDs) more than seven times brighter by etching nanoscale grooves in a surrounding cavity to guide scattered light in one direction. The novel nanostructure, which may have applications in areas such as in biomedical imaging where LED brightness is crucial, is described in the July 17 issue of Applied Physics Letters.

Etched nanostructured rings around an LED can make it more than seven times brighter. The novel technique developed at NIST may have applications in areas such as in biomedical imaging where LED brightness is crucial.
Credit: Image courtesy of National Institute of Standards and Technology

Researchers at the National Institute of Standards and Technology (NIST) have made semiconductor light-emitting diodes (LEDs) more than seven times brighter by etching nanoscale grooves in a surrounding cavity to guide scattered light in one direction. The novel nanostructure, which may have applications in areas such as in biomedical imaging where LED brightness is crucial, is described in the July 17 issue of Applied Physics Letters.*

Semiconductor LEDs are used increasingly in displays and many other applications, in part because they can efficiently produce light across a broad spectrum, from near-infrared to the ultraviolet. However, they typically emit only about two percent of the light in the desired direction: perpendicular to the diode surface. Far more light skims uselessly below the surface of the LED, because of the extreme mismatch in refraction between air and the semiconductor. The NIST nanostructured cavity boosts useful LED emission to about 41 percent and may be cheaper and more effective for some applications than conventional post-processing LED shaping and packaging methods that attempt to redirect light.

The NIST team fabricated their own infrared LEDs consisting of gallium arsenide packed with "quantum dots" of assorted sizes made of indium gallium arsenide. Quantum dots are nanoscale semiconductor particles that efficiently emit light at a color determined by the exact size of the particle. The LEDs were backed with an alumina mirror to reflect the light emitted backwards. The periphery of each LED was turned into a cavity etched with circular grooves, in which the light reflects and interferes with itself in an optimal geometry.

The researchers experimented with different numbers and dimensions of grooves. The brightest output was attained with 10 grooves, each about 240 nanometers (nm) wide and 150 nm deep, and spaced 40 nm apart. The team spent several years developing the design principles and perfecting the manufacturing technique. The principles of the method are transferable to other LED materials and emission wavelengths, as well as other processing techniques, such as commercial photolithography, according to lead author Mark Su.


Story Source:

The above story is based on materials provided by National Institute of Standards and Technology. Note: Materials may be edited for content and length.


Cite This Page:

National Institute of Standards and Technology. "Novel Nano-etched Cavity Makes LEDs 7 Times Brighter." ScienceDaily. ScienceDaily, 23 July 2006. <www.sciencedaily.com/releases/2006/07/060721195354.htm>.
National Institute of Standards and Technology. (2006, July 23). Novel Nano-etched Cavity Makes LEDs 7 Times Brighter. ScienceDaily. Retrieved April 16, 2014 from www.sciencedaily.com/releases/2006/07/060721195354.htm
National Institute of Standards and Technology. "Novel Nano-etched Cavity Makes LEDs 7 Times Brighter." ScienceDaily. www.sciencedaily.com/releases/2006/07/060721195354.htm (accessed April 16, 2014).

Share This



More Matter & Energy News

Wednesday, April 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Google Patents Contact Lens Cameras; Internet Is Wary

Google Patents Contact Lens Cameras; Internet Is Wary

Newsy (Apr. 15, 2014) Google has filed for a patent to develop contact lenses capable of taking photos. The company describes possible benefits to blind people. Video provided by Newsy
Powered by NewsLook.com
The Walking, Talking Oil-Drigging Rig

The Walking, Talking Oil-Drigging Rig

Reuters - Business Video Online (Apr. 15, 2014) Pennsylvania-based Schramm is incorporating modern technology in its next generation oil-drigging rigs, making them smaller, safer and smarter. Ernest Scheyder reports. Video provided by Reuters
Powered by NewsLook.com
Dutch Highway Introduces Glow-In-The-Dark Paint

Dutch Highway Introduces Glow-In-The-Dark Paint

Newsy (Apr. 14, 2014) A Dutch highway has become the first lit by glow-in-the-dark paint — a project aimed at reducing street light use. Video provided by Newsy
Powered by NewsLook.com
Google Buys Drone Maker, Hopes to Connect Rural World

Google Buys Drone Maker, Hopes to Connect Rural World

Newsy (Apr. 14, 2014) Formerly courted by Facebook, Titan Aerospace will become a part of Google's quest to blanket the world in Internet connectivity. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins