Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International

Wikipedia Affiliate Button

Home > Press > Don't blink! NIST studies why quantum dots suffer from 'fluorescence intermittency'

Abstract:
Researchers at the National Institute of Standards and Technology (NIST), working in collaboration with the Naval Research Laboratory, have found that a particular species of quantum dots that weren't commonly thought to blink, do.

Don't blink! NIST studies why quantum dots suffer from 'fluorescence intermittency'

Gaithersburg, MD | Posted on May 22nd, 2014

So what? Well, although the blinks are short—on the order of nanoseconds to milliseconds—even brief fluctuations can result in efficiency losses that could cause trouble for using quantum dots to generate photons that move information around inside a quantum computer or between nodes of a future high-security internet based on quantum telecommunications.

Beyond demonstrating that the dots are blinking, the team also suggests a possible culprit.*

Scientists have regarded indium arsenide and gallium arsenide (InAs/GaAs) quantum dots to be promising as single photon sources foruse in different future computing and communication systems based on quantum technologies. Compared to other systems, researchers have preferred these quantum dots because they appeared to not blink and because they can be fabricated directly into the types of semiconductor optoelectronics that have been developing over the past few decades.

The NIST research team also thought these quantum dots were emitting steady light perfectly, until they came upon one that was obviously blinking (or was "fluorescently intermittent," in technical terms). They decided to see if they could find others that were blinking in a less obvious way.

While most previous experiments surveyed the dots in bulk, the team tested these dots as they would be used in an actual device. Using an extremely sensitive photon autocorrelation technique to uncover subtle signatures of blinking, they found that the dots blink over timescales rangingfrom tens of nanoseconds to hundreds of milliseconds. Their results suggest that building photonic structures around the quantum dots—something you'd have to do to make many applications viable—may make them significantly less stable as a light source.

"Most of the previous experimental studies of blinking inInAs/GaAs quantum dots looked at their behavior after the dots have been grown but before the surrounding devices have been fabricated," says Kartik Srinivasan, one of the authors of the study. "However, there is no guarantee that a quantum dot will remain non-blinking after the nanofabrication of a surrounding structure, which introduces surfaces and potential defects within 100 nanometers of the quantum dot. We estimate the radiative efficiency of the quantum dots to be between about 50 and 80 percent after the photonic structures are fabricated, significantly less than the 100 percent efficiency that future applications will require."

According to Marcelo Davanço, another author of the study, future work will focus on measuring dots both before and after device fabrication to better assess whether the fabrication is indeed a source of the defects thought to cause the blinking. Ultimately, the authors hope to understand what types of device geometries will avoid blinking while still efficiently funneling the emitted photons into a useful transmission channel, such as an optical fiber.

####

About National Institute of Standards and Technology (NIST)
The National Institute of Standards and Technology (NIST) is an agency of the U.S. Department of Commerce.

The NIST Center for Nanoscale Science and Technology (CNST) is a national nanotechnology user facility that enables innovation by providing rapid access to the tools needed to make and measure nanostructures. Researchers interested in accessing the techniques described here or in collaborating on their future development should contact Kartik Srinivasan.

For more information, please click here

Contacts:
Mark Esser

301-975-8735

Copyright © National Institute of Standards and Technology (NIST)

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

*M. Davanço, C. Stephen Hellberg, S. Ates, A. Badolato and K. Srinivasan. Multiple time scale blinking in InAs quantum dot single-photon sources. Phys. Rev. B 89, 161303(R) – Published 16 April 2014:

Related News Press

News and information

Artificial photosynthesis transforms carbon dioxide into liquefiable fuels May 22nd, 2019

Neutrons unlock the secrets of limoncello May 21st, 2019

Machine learning speeds modeling of experiments aimed at capturing fusion energy on Earth May 17th, 2019

Manipulating atoms one at a time with an electron beam: New method could be useful for building quantum sensors and computers May 17th, 2019

Laboratories

Machine learning speeds modeling of experiments aimed at capturing fusion energy on Earth May 17th, 2019

Manipulating atoms one at a time with an electron beam: New method could be useful for building quantum sensors and computers May 17th, 2019

Govt.-Legislation/Regulation/Funding/Policy

Machine learning speeds modeling of experiments aimed at capturing fusion energy on Earth May 17th, 2019

Manipulating atoms one at a time with an electron beam: New method could be useful for building quantum sensors and computers May 17th, 2019

New way to beat the heat in electronics: Rice University lab's flexible insulator offers high strength and superior thermal conduction May 16th, 2019

New Argonne coating could have big implications for lithium batteries May 14th, 2019

Optical computing/Photonic computing

2D borophene gets a closer look: Rice, Northwestern find new ways to image, characterize unique material April 11th, 2019

When semiconductors stick together, materials go quantum: A new study led by Berkeley Lab reveals how aligned layers of atomically thin semiconductors can yield an exotic new quantum material March 12th, 2019

New blueprint for understanding, predicting and optimizing complex nanoparticles: Guidelines have the potential to transform the fields of optoelectronics, bio-imaging and energy harvesting March 1st, 2019

Researchers move closer to practical photonic quantum computing: New method fills critical need to measure large-scale quantum correlation of single photons February 28th, 2019

Discoveries

Artificial photosynthesis transforms carbon dioxide into liquefiable fuels May 22nd, 2019

Neutrons unlock the secrets of limoncello May 21st, 2019

Manipulating atoms one at a time with an electron beam: New method could be useful for building quantum sensors and computers May 17th, 2019

New surface treatment could improve refrigeration efficiency: A slippery surface for liquids with very low surface tension promotes droplet formation, facilitating heat transfer May 17th, 2019

Announcements

Artificial photosynthesis transforms carbon dioxide into liquefiable fuels May 22nd, 2019

Neutrons unlock the secrets of limoncello May 21st, 2019

Manipulating atoms one at a time with an electron beam: New method could be useful for building quantum sensors and computers May 17th, 2019

New surface treatment could improve refrigeration efficiency: A slippery surface for liquids with very low surface tension promotes droplet formation, facilitating heat transfer May 17th, 2019

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Artificial photosynthesis transforms carbon dioxide into liquefiable fuels May 22nd, 2019

Machine learning speeds modeling of experiments aimed at capturing fusion energy on Earth May 17th, 2019

Manipulating atoms one at a time with an electron beam: New method could be useful for building quantum sensors and computers May 17th, 2019

Generating high-quality single photons for quantum computing: New dual-cavity design emits more single photons that can carry quantum information at room temperature May 17th, 2019

Military

Manipulating atoms one at a time with an electron beam: New method could be useful for building quantum sensors and computers May 17th, 2019

New way to beat the heat in electronics: Rice University lab's flexible insulator offers high strength and superior thermal conduction May 16th, 2019

Army discovery opens path to safer batteries May 10th, 2019

Self-powered wearable tech May 8th, 2019

Quantum Dots/Rods

Coal could yield treatment for traumatic injuries: Rice, Texas A&M, UTHealth scientists discover coal-derived ‘dots’ are effective antioxidant April 25th, 2019

2D gold quantum dots are atomically tunable with nanotubes April 11th, 2019

Tracking pollen with quantum dots: A pollination biologist from Stellenbosch University in South Africa is using quantum dots to track the fate of individual pollen grains. This is breaking new ground in a field of research that has been hampered by the lack of a universal method February 17th, 2019

Machine learning helps improving photonic applications September 28th, 2018

Photonics/Optics/Lasers

Sculpting Super-Fast Light Pulses: NIST Nanopillars Shape Light Precisely for Practical Applications May 3rd, 2019

2D borophene gets a closer look: Rice, Northwestern find new ways to image, characterize unique material April 11th, 2019

New hybrid energy method could fuel the future of rockets, spacecraft for exploration: Nontraditional route shown to increase performance, burn rate April 9th, 2019

Nanoscribe is Technology Partner of the Research Project MiLiQuant: 3D microfabrication meets quantum technology - Miniaturized light sources for industrial use in the fields of quantum sensor technology and quantum imaging April 1st, 2019

Research partnerships

Manipulating atoms one at a time with an electron beam: New method could be useful for building quantum sensors and computers May 17th, 2019

New Argonne coating could have big implications for lithium batteries May 14th, 2019

Sculpting Super-Fast Light Pulses: NIST Nanopillars Shape Light Precisely for Practical Applications May 3rd, 2019

Exploring New Ways to Control Thermal Radiation April 29th, 2019

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project