Featured Research

from universities, journals, and other organizations

Switchable Two-color Light Source On A Silicon Chip

Date:
May 28, 2007
Source:
Forschungszentrum Dresden Rossendorf
Summary:
Silicon is the most important material for electronic chips and processors. Yet it has a big drawback: it is considered an indirect semiconductor -- it hardly emits any light. Therefore worldwide efforts in the labs of the microelectronics industry are aimed towards developing more efficient light sources based on silicon. Physicists have now managed to make silicon shine red and blue in an alternating fashion. This two-color light source could help to produce cheap and compact biosensors.

Photographs of the multi-color light emitter, 200 micrometer in diameter, taken under a microscope: the electrical current was 0.02 mA (a), 1 mA (b) and 2.5 mA (c), respectively. The violet color in (c) is a result of mixing the red and the blue.
Credit: Image courtesy of Forschungszentrum Dresden Rossendorf

Silicon is the most important material for electronic chips and processors. Yet it has a big drawback: being a so-called indirect semiconductor, it hardly emits any light. Therefore worldwide efforts in the labs of the microelectronics industry are aimed towards developing more efficient light sources based on silicon. Physicists at the Forschungszentrum Dresden-Rossendorf (FZD) now managed to make silicon shine red and blue in an alternating fashion. This two-color light source could help to produce cheap and compact biosensors. Recently a patent was filed related to this discovery.

It is not an easy task to make silicon shine, or, more accurately, to generate electroluminescence from this material, since in its usual form it can only emit with a very low efficiency. The Forschungszentrum Dresden-Rossendorf has worked successfully for several years on the realization of silicon based light emitters. Initially the physicists made a blue-violet emitter, which was then the basis of a silicon based optocoupler.

In 2004 they demonstrated ultraviolet, and then green light emitters. Now the physicists can switch the characteristics of the emitted light between two colors – red and blue – at will, depending only on the electrical current flowing through the device. The compatibility of these emitters with standard Silicon microelectronic technology is crucial, since the two-color nano-switch could easily integrated into common silicon chips.

For the fabrication of the test devices the group around Dr. Wolfgang Skorupa deposits an only 100 nanometer (one nanometer is one millionth of a millimeter) thin insulating silicon dioxide layer on the surface of the silicon wafer. Then the element Europium, which belongs to the group of rare-earth elements, is implanted using a beam of fast, charged atoms (ion beam). The peculiarity of Europium lies in the fact that it forms two different types of impurities carrying a different charge (oxidation state). These are the origin of the red and blue luminescence. Depending on the strength of the electrical current one or the other impurity type is excited to emit photons.

Possible applications of this two-color device lie in the area of biosensing. For example, the new silicon based light source could be used in the fast and cost-effective point-of-care analysis in health and environmental protection.

Reference: S. Prucnal, W. Skorupa, J. M. Sun, M. Helm, "Switchable two-color electroluminescence based on a Si metal-oxide-semiconductor structure doped with Eu“, in: Applied Physics Letters 90, 181121 (2007).


Story Source:

The above story is based on materials provided by Forschungszentrum Dresden Rossendorf. Note: Materials may be edited for content and length.


Cite This Page:

Forschungszentrum Dresden Rossendorf. "Switchable Two-color Light Source On A Silicon Chip." ScienceDaily. ScienceDaily, 28 May 2007. <www.sciencedaily.com/releases/2007/05/070527194838.htm>.
Forschungszentrum Dresden Rossendorf. (2007, May 28). Switchable Two-color Light Source On A Silicon Chip. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2007/05/070527194838.htm
Forschungszentrum Dresden Rossendorf. "Switchable Two-color Light Source On A Silicon Chip." ScienceDaily. www.sciencedaily.com/releases/2007/05/070527194838.htm (accessed August 1, 2014).

Share This




More Matter & Energy News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
7 Ways to Use Toothpaste: Howdini Hacks

7 Ways to Use Toothpaste: Howdini Hacks

Howdini (July 30, 2014) Fresh breath and clean teeth are great, but have you ever thought, "my toothpaste could be doing more". Well, it can! Lots of things! Howdini has 7 new uses for this household staple. Video provided by Howdini
Powered by NewsLook.com
Amid Drought, UCLA Sees Only Water

Amid Drought, UCLA Sees Only Water

AP (July 30, 2014) A ruptured 93-year-old water main left the UCLA campus awash in 8 million gallons of water in the middle of California's worst drought in decades. (July 30) Video provided by AP
Powered by NewsLook.com
Smartphone Powered Paper Plane Debuts at Airshow

Smartphone Powered Paper Plane Debuts at Airshow

AP (July 30, 2014) Smartphone powered paper airplane that was popular on crowdfunding website KickStarter makes its debut at Wisconsin airshow (July 30) Video provided by AP
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