Powerful gallium nitride red light-emitting diodes made with europium and magnesium codoping

Jun 28, 2013
Powerful gallium nitride red light-emitting diodes made with europium and magnesium codoping
Fig. 1 Typical emission image of Eu doped GaN based LED.

(Phys.org) —Toyohashi Tech researchers fabricate powerful red light-emitting diodes by codoping GaN with Eu and Mg. The details are described in the June 2013 issue of Toyohashi Tech e-Newsletter: http://www.tut.ac.jp/english/newsletter/index.html

Europium (Eu) doped nitride semiconductors show potential for realization of novel optical devices, such as a low threshold lasers and single photon emitters, due to their sharp line and high efficiency emission.

However, not all the Eu ions in semiconductor are incorporated in optically active sites that can be excited through the GaN host. Therefore, it is important to develop methods to selectively incorporate Eu ions in higher-efficiency optical sites.

Here, Hiroto Sekiguchi and colleagues at Toyohashi University of Technology and Hamamatsu Photonics Ltd have improved the emission intensity from Eu ions by Mg co-doping and fabricated LEDs with Eu and Mg doped active layer grown by ammonia source MBE.

The optimal Mg co-doping selectively enhanced a specific emission site and contributed to a (PL) intensity increase of more than one order of magnitude. From the ratio of PL integrated intensity at 25 K to that at 300 K, the PL efficiency was determined to be as high as 77%. On the basis of these results, Eu doped GaN based LEDs were fabricated. Clear rectification characteristics with a turn-on voltage of 3.2 V were observed and a pure red emission was observed by the naked eye at room temperature. These results suggest that Eu and Mg doped GaN is expected to be utilized for realizing new nitride-based light-emitting devices.

Explore further: Perfectly doped quantum dots yield colors to dye for

More information: Sekiguchi, H. et al. Red-Light-Emitting Diodes with Site-Selective Eu-Doped GaN Active Layer, Jpn. J. Appl. Phys. 52 (2013). DOI: 10.7567/JJAP.52.08JH01

add to favorites email to friend print save as pdf

Related Stories

Perfectly doped quantum dots yield colors to dye for

May 10, 2013

(Phys.org) —Quantum dots are tiny nanocrystals with extraordinary optical and electrical properties with possible uses in dye production, bioimaging, and solar energy production. Researchers at the University ...

Conquering LED efficiency droop

Apr 30, 2012

WASHINGTON, April 30--Like a coffee enthusiast who struggles to get a buzz from that third cup of morning joe, light-emitting diodes (LEDs) seem to reach a point where more electricity no longer imparts the ...

Recommended for you

Growing app industry has developers racing to keep up

8 hours ago

Smartphone application developers say they are challenged by the glut of apps as well as the need to update their software to keep up with evolving phone technology, making creative pricing strategies essential to finding ...

Review: With Galaxy S5, Samsung proves less can be more

10 hours ago

Samsung Electronics Co. has produced the most formidable rival yet to the iPhone 5S: the Galaxy S5. The device, released over the weekend, is the fifth edition of the company's successful line of Galaxy S ...

User comments : 0

More news stories

Growing app industry has developers racing to keep up

Smartphone application developers say they are challenged by the glut of apps as well as the need to update their software to keep up with evolving phone technology, making creative pricing strategies essential to finding ...

Making graphene in your kitchen

Graphene has been touted as a wonder material—the world's thinnest substance, but super-strong. Now scientists say it is so easy to make you could produce some in your kitchen.