Navigation Links
Scientists scale terahertz peaks in nanotubes
Date:12/9/2013

HOUSTON (Dec. 9, 2013) Carbon nanotubes carry plasmonic signals in the terahertz range of the electromagnetic spectrum, but only if they're metallic by nature or doped.

In new research, the Rice University laboratory of physicist Junichiro Kono disproved previous theories that dominant terahertz response comes from narrow-gap semiconducting nanotubes.

Knowing that metallic or doped nanotubes respond with plasmonic waves at terahertz frequencies opens up the possibility that the tubes can be used in a wide array of optoelectronic amplifiers, detectors, polarizers and antennas.

The work by Kono and his Rice colleagues appeared online recently in the American Chemical Society journal Nano Letters.

Scientists have long been aware of a terahertz peak in nanotubes, the tiny cylinders of rolled-up carbon that show so much promise for advanced materials. But experiments on batches of nanotubes, which generally grow in a willy-nilly array of types, failed to reveal why it was there.

The origin of the peak was not explainable because researchers were only able to experiment on mixed batches of nanotube types, said Qi Zhang, a graduate student in Kono's group and lead author of the paper. "All the previous work was done with a mixture of semiconducting and metallic tubes. We are the first to clearly identify the plasmonic nature of this terahertz response," he said.

Rice's growing expertise in separating nanotubes by type allowed Kono and his group to test for terahertz peaks in batches of pure metallic nanotubes known as "armchairs" as well as nonmetallic, semiconducting tubes.

"Metallic carbon nanotubes are expected to show plasmon resonance in the terahertz and infrared range, but no group has clearly demonstrated the existence of plasmons in carbon nanotubes," Zhang said. "Previously, people proposed one possible explanation -- that the terahertz peak is due to interband absorption in the small band gaps in semiconducting nanotubes. We rejected that in this paper."

Plasmons are free electrons on the surface of metals like gold, silver or even aluminum nanoparticles that, when triggered by a laser or other outside energy, ripple like waves in a pond. Strong waves can trigger plasmon responses in adjacent nanoparticles. They are being investigated at Rice and elsewhere for use in sophisticated electronic and medical applications.

The Kono group's research showed plasmons rippling at terahertz frequencies only along the length of a nanotube, but not across its width. "The only way charge carriers can move around is in the long direction," Kono said. The researchers previously used this fact to demonstrate that aligned carbon nanotubes act as an excellent terahertz polarizer with performance better than commercial polarizers based on metallic grids.

Nanotubes can be thousands of times longer than they are wide, and the ability to grow them (or cut them) to specific lengths or to dope semiconducting nanotubes to add free carriers would make the tubes highly tunable for terahertz frequencies, Kono said.

"This paper only clarifies the origin of this effect," he said. "Now that we understand it, there's so much to do. We will be making various terahertz devices, architectures and systems based on carbon nanotube plasmons."


'/>"/>

Contact: David Ruth
david@rice.edu
713-348-6327
Rice University
Source:Eurekalert  

Related biology technology :

1. Scientists defuse the Vietnam time bomb
2. Singapore scientists lead human embryonic stem cell study
3. Sheffield scientists shine a light on the detection of bacterial infection
4. Nanowiggles: Scientists discover graphene nanomaterials with tunable functionality in electronics
5. Scientists solve mystery of colorful armchair nanotubes
6. iBioSeminars and iBioMagazine: Free, Online Biology Seminars and Short Talks by Leading Scientists
7. Chinese Scientists Zhen-Yi Wang and Zhu Chen Awarded 7th Annual Szent-Gyorgyi Prize for Progress in Cancer Research
8. Scientists decode brain waves to eavesdrop on what we hear
9. Receptos Scientists Publish Determination of a High Resolution Sphingosine 1-Phosphate Receptor 1 Structure in Science
10. Scientists learn how to out run damage with imaging technique
11. Design eye for the science guy: Drop-in clinic helps scientists communicate data
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Scientists scale terahertz peaks in nanotubes
(Date:6/24/2016)... Brooklyn, NY (PRWEB) , ... June 24, 2016 , ... ... 15mm, machines such as the Cary 5000 and the 6000i models are higher end ... height is the height of the spectrophotometer’s light beam from the bottom of the ...
(Date:6/23/2016)... ... June 23, 2016 , ... Mosio, a ... eBook, “Clinical Trials Patient Recruitment and Retention Tips.” Partnering with experienced clinical research ... by providing practical tips, tools, and strategies for clinical researchers. , “The landscape ...
(Date:6/23/2016)...   Boston Biomedical , an industry leader ... target cancer stemness pathways, announced that its lead ... Designation from the U.S. Food and Drug Administration ... gastroesophageal junction (GEJ) cancer. Napabucasin is an orally ... stemness pathways by targeting STAT3, and is currently ...
(Date:6/23/2016)... 23, 2016 A person commits a crime, and ... to track the criminal down. An outbreak of ... Drug Administration (FDA) uses DNA evidence to track down the ... Sound far-fetched? It,s not. The FDA has increasingly used a ... of foodborne illnesses. Put as simply as possible, whole genome ...
Breaking Biology Technology:
(Date:6/2/2016)... , June 2, 2016   The Weather Company , ... Watson Ads, an industry-first capability in which consumers will be ... able to ask questions via voice or text and receive ... Marketers have long sought an advertising ... that can be personal, relevant and valuable; and can scale ...
(Date:5/24/2016)... Ampronix facilitates superior patient care by providing unparalleled technology to leaders of ... the latest premium product recently added to the range of products distributed by Ampronix. ... ... ... Medical Display- Ampronix News ...
(Date:5/12/2016)... , May 12, 2016 WearablesResearch.com ... just published the overview results from the Q1 wave ... the recent wave was consumers, receptivity to a program ... data with a health insurance company. "We ... to share," says Michael LaColla , CEO of ...
Breaking Biology News(10 mins):