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:1/18/2017)... ... January 18, 2017 , ... DrugDev ... for Clinical Ops Executives (Hyatt Regency Miami, January 24-26). DrugDev will join customers ... research issues such as trial performance metrics, patient enrollment diversity, protocol optimization, and ...
(Date:1/18/2017)... ... January 18, 2017 , ... ... of the latest paper by its Science Editor, Dr. Elisabeth Bik, in the ... Medische Microbiologie). Dr. Bik joined uBiome in October 2016 from her previous position ...
(Date:1/18/2017)... 2017 Shareholder rights law firm Johnson & ... board members of CoLucid Pharmaceuticals, Inc. (NASDAQ: ... the proposed sale of the Company to Eli Lilly ... small molecules for the acute treatment of migraines. ... signed a definitive merger agreement with Eli Lilly. Under ...
(Date:1/18/2017)... 2017  Caris Life Sciences, a leading innovator ... largest private funder of pancreatic cancer research, are ... impact of immunotherapy in the treatment of pancreatic ... to identify potential trial candidates based on biomarker ... and study investigators. The Lustgarten Foundation is a ...
Breaking Biology Technology:
(Date:12/15/2016)... Calif. , Dec. 15, 2016   WaferGen ... publicly held genomics technology company, announced today that on ... Listing Qualifications Department of The Nasdaq Stock Market LLC ... closing bid price of WaferGen,s common stock had been ... Accordingly, WaferGen has regained compliance with Listing Rule 5550(a)(2) ...
(Date:12/15/2016)... 14, 2016 "Increase in mobile transactions is ... mobile biometrics market is expected to grow from USD ... 2022, at a CAGR of 29.3% between 2016 and ... the growing demand for smart devices, government initiatives, and ... "Software component is expected to grow at a high ...
(Date:12/7/2016)... 2016 According to a new market research report "Emotion ... Expression, Voice Recognition), Service, Application Area, End User, And Region - Global Forecast ... USD 6.72 Billion in 2016 to USD 36.07 Billion by 2021, at a ... Reading ... MarketsandMarkets Logo ...
Breaking Biology News(10 mins):