Featured Research

from universities, journals, and other organizations

Plasmonics: Minimizing loss by thinning, smoothing

Date:
July 8, 2014
Source:
The Agency for Science, Technology and Research (A*STAR)
Summary:
A gas cluster ion beam smoothing produces ultrathin silver films and lithographically patterned structures to enhance plasmonic performance, researchers report. Plasmonic devices -- such as superlenses, hyperlenses and plasmonic waveguides -- have exciting potential for research and commercial applications because they permit optical lithography, imaging and waveguiding to be performed at resolutions below the diffraction limit of light.

The smoothing effect of a gas cluster ion beam (purple) on a rough surface (gray).
Credit: 2014 A*STAR Institute of Materials Research and Engineering

A gas cluster ion beam smoothing produces ultrathin silver films and lithographically patterned structures to enhance plasmonic performance.

Related Articles


Plasmonic devices -- such as superlenses, hyperlenses and plasmonic waveguides -- have exciting potential for research and commercial applications because they permit optical lithography, imaging and waveguiding to be performed at resolutions below the diffraction limit of light. These devices often require low-loss ultrathin metal films, which are difficult to fabricate using current deposition techniques. Researchers have investigated processes such as seed layer deposition and thermal annealing to reduce the surface roughness and grain-boundary density of these films. To date, however, these processes have not been hugely successful.

Now, Ee Jin Teo and colleagues at the A*STAR Institute of Materials Research and Engineering, Singapore, the University of Hyogo, Japan, and the National University of Singapore have used gas cluster ion beam (GCIB) processing to smooth ultrathin metal films and thereby enhance their properties(1). A GCIB consists of thousands of gas molecules that are weakly bound by van der Waals forces. Such a beam is able to smooth out surface irregularities and reduce film thickness with nanometer precision. This processing significantly enhances surface plasmon resonance and propagation, and enables the fabrication of ultrathin films with extremely low electrical resistivity and optical loss.

Unlike monomer ion beams used in conventional ion-beam milling and plasma etching, a cluster of nitrogen gas molecules with an energy of 20 kiloelectron volts impinging on a silver film can deliver a high energy density to a relatively small volume: yet the cluster penetrates to a depth of only a few nanometers. The impact of the beam on the film causes silver atoms in surface peaks to scatter sideways towards valleys, voids and grain boundaries. As well as producing a smoother surface, this processing triples the grain width through the redeposition of atoms at grain boundaries.

The team's GCIB treatment resulted in up to a four-fold improvement in the electrical and optical properties of films of a thickness of 12 nanometers. "The unique characteristics of GCIB irradiation meant that in a single irradiation step we could reduce scattering losses due to surface roughness, grain boundaries and voids," notes Teo.

The research team also used the technique to smooth the top surface and sidewalls of lithographically patterned silver-stripe waveguides, increasing the propagation lengths of surface plasmons in these waveguides.

"In the future, we intend to use this technique to improve the colour purity of plasmonic color filters or reflectors, and also to increase the patterned area of superlens nanolithography," says Teo. "Such developments will bring plasmonic research a step closer to commercialization."


Story Source:

The above story is based on materials provided by The Agency for Science, Technology and Research (A*STAR). Note: Materials may be edited for content and length.


Journal Reference:

  1. Ee Jin Teo, Noriaki Toyoda, Chengyuan Yang, Bing Wang, Nan Zhang, Andrew A. Bettiol, Jing Hua Teng. Sub-30 nm thick plasmonic films and structures with ultralow loss. Nanoscale, 2014; 6 (6): 3243 DOI: 10.1039/C3NR05502G

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Plasmonics: Minimizing loss by thinning, smoothing." ScienceDaily. ScienceDaily, 8 July 2014. <www.sciencedaily.com/releases/2014/07/140708111013.htm>.
The Agency for Science, Technology and Research (A*STAR). (2014, July 8). Plasmonics: Minimizing loss by thinning, smoothing. ScienceDaily. Retrieved November 23, 2014 from www.sciencedaily.com/releases/2014/07/140708111013.htm
The Agency for Science, Technology and Research (A*STAR). "Plasmonics: Minimizing loss by thinning, smoothing." ScienceDaily. www.sciencedaily.com/releases/2014/07/140708111013.htm (accessed November 23, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Sunday, November 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Newsy (Nov. 23, 2014) Microsoft has robotic security guards working at its Silicon Valley Campus. Video provided by Newsy
Powered by NewsLook.com
Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

AFP (Nov. 21, 2014) Toyota presented its hydrogen fuel-cell compact car called "Mirai" to US consumers at the Los Angeles auto show. The car should go on sale in 2015 for around $60.000. It combines stored hydrogen with oxygen to generate its own power. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
Google Announces Improvements To Balloon-Borne Wi-Fi Project

Google Announces Improvements To Balloon-Borne Wi-Fi Project

Newsy (Nov. 21, 2014) In a blog post, Google said its balloons have traveled 3 million kilometers since the start of Project Loon. Video provided by Newsy
Powered by NewsLook.com
Raw: Paralyzed Marine Walks With Robotic Braces

Raw: Paralyzed Marine Walks With Robotic Braces

AP (Nov. 21, 2014) Marine Corps officials say a special operations officer left paralyzed by a sniper's bullet in Afghanistan walked using robotic leg braces in a ceremony to award him a Bronze Star. (Nov. 21) 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:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

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