Navigation Links
'High Q' NIST nanowires may be practical oscillators
Date:11/27/2007

Nanowires grown at the National Institute of Standards and Technology (NIST) have a mechanical quality factor at least 10 times higher than reported values for other nanoscale devices such as carbon nanotubes, and comparable to that of commercial quartz crystals. Because a high Q factor indicates a capacity for stable vibrations, the nanowires might be used as oscillators in nano-electromechanical systems for future nano-sensors and communications devices.

We think the most interesting thing about these wires is the very high quality factor observed for such a small object, says NIST researcher and co-author Kris Bertness, who grew the nanowires.

NIST has developed a unique way of growing hexagonal gallium nitride (GaN) nanowires featuring low defect density and high luminescence intensity. In a new paper*, researchers at NIST and the University of Colorado at Boulder report high Q factors in wires that are 30 to 500 nanometers in diameter and 5 to 20 micrometers long, vibrating between 400,000 and 2.8 million times per second. (For comparison, the quartz crystals used in watches usually vibrate about 32,000 times a second.) The nanowires vibrated when placed on a piezoelectric device stimulated by an electrical signal. The nanowires also oscillated when excited directly by an electron beam, apparently due to the GaN materials intrinsic piezoelectric ability to covert voltage to mechanical force.

Q measures the damping of oscillations in a mechanical system as a function of frequencythe higher its Q, the longer a bell rings after being struck. Ordinarily, Q factors of mechanical resonators tend to drop as their diameters shrink. But GaN nanowires have a number of properties that may boost their Q and make them suitable as practical oscillators. They have extremely flat and smooth surfaces (irregularities have reduced performance in other oscillators.) GaN also has a resonant frequency similar to silicon (commonly used in microelectronics) but is less susceptible to some sources of noise. Finally, GaN has high heat capacity and thermal conductivity, reducing sensitivity to temperature fluctuations. Another practical advantage is that NISTs GaN nanowires are grown on silicon, making them compatible with existing microelectronics processing methods.

To measure the resonance properties of the nanowires, researchers observed clumps of nanowires using a scanning electron microscope. As the frequency of the applied signal was varied across a range, the nanowires seen in micrographs appear to blur or fan out at or near the resonance frequency. For the nanowire shown in the image, the Q value (about 38,000) is at least 10 times higher than previously reported values for other GaN nanowires, carbon nanotubes, and single-crystal silicon microstructures of similar surface-to-volume ratio. The researchers have measured Q values of more than 1 million in resonating GaN nanowires using feedback (like continuous striking of a bell to keep it ringing), as would occur in a real device.


'/>"/>

Contact: Laura Ost
laura.ost@nist.gov
303-497-4880
National Institute of Standards and Technology (NIST)  
Source:Eurekalert

Related biology technology :

1. Dendreon Announces Publication of Phase 1 Study Highlighting Immunologic and Clinical Activity of Lapuleucel-T (Neuvenge(R)) in Advanced Breast Cancer Patients
2. Pharmatek Adds Cytotoxic and High-Potent Drug Development Capabilities to San Diego Laboratory
3. ImmuneRegen BioSciences Files 8-K that Highlights Enclosed Shareholder Letter Discussing Recent Achievements and Outlook
4. KAPE to Honor High-Performing Pennsylvania Organizations
5. SportCoatings; The North American Booster Club Association (NABCA); the Coatings Specialist Group New Booster Program Goes High Tech With Invisible Antimicrobial Defense
6. Safety Profile of TAXUS(R) Liberte(TM) Stent System Highlighted in Worlds Largest Stent Registry
7. New Survey Reveals Many Adults With High Cholesterol Fail to Take Necessary Steps to Improve Their Condition
8. Stimuvax(R) Phase II data highlight three-year survival results for patients with non-small cell lung cancer
9. Three Studies by Independent Scientists Highlighting Pressure Cycling Technology (PCT) to be Presented this Week at the British Mass Spectrometry Societys 29th Annual Meeting
10. Access Highlighted in Recent BusinessWeek Article
11. Caliper Life Sciences Introduces High Throughput RNA Assay to Improve Workflow in Gene Expression Studies
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
'High Q' NIST nanowires may be practical oscillators
(Date:6/23/2016)... , June 23, 2016   Boston ... of novel compounds designed to target cancer stemness ... has been granted Orphan Drug Designation from the ... treatment of gastric cancer, including gastroesophageal junction (GEJ) ... inhibitor designed to inhibit cancer stemness pathways by ...
(Date:6/23/2016)... SILVER SPRING, Md. , June 23, 2016 ... evidence collected from the crime scene to track the criminal ... sick, and the U.S. Food and Drug Administration (FDA) uses ... Sound far-fetched? It,s not. ... whole genome sequencing to support investigations of foodborne illnesses. Put ...
(Date:6/23/2016)... ... June 23, 2016 , ... Charm Sciences, ... microbial test has received AOAC Research Institute approval 061601. , “This is another ... year,” stated Bob Salter, Vice President of Regulatory and Industrial Affairs. “The Peel ...
(Date:6/23/2016)... NEW YORK , June, 23, 2016  The ... students to envision new ways to harness living systems ... of Modern Art (MoMA) in New York ... more than 130 participating students, showcased projects at MoMA,s ... included Paola Antonelli , MoMA,s senior curator of ...
Breaking Biology Technology:
(Date:6/2/2016)... The Department of Transport Management (DOTM) ... million US Dollar project, for the , Supply ... Enrolment, and IT Infrastructure , to ... implementation of Identity Management Solutions. Numerous renowned international vendors participated ... was selected for the most compliant and innovative ...
(Date:6/2/2016)... Perimeter Surveillance & Detection Systems, Biometrics & ... & Other Service  The latest report from ... of the global Border Security market . Visiongain ... billion in 2016. Now: In November 2015 ... and hardware technologies for advanced video surveillance. ...
(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. ... ... ... Display- Ampronix News ...
Breaking Biology News(10 mins):