Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > NRL researchers control the spin of semiconductor quantum dot shell states

Semiconductor QDs are nanoscale circular disks of one semiconducting material, typically 3 nm high by 30 nm in diameter, embedded within layers of a second material.

Credit: Naval Research Laboratory
Semiconductor QDs are nanoscale circular disks of one semiconducting material, typically 3 nm high by 30 nm in diameter, embedded within layers of a second material.

Credit: Naval Research Laboratory

Abstract:
Scientists at the Naval Research Laboratory (NRL) have recently demonstrated the ability to control the spin population of the individual quantum shell states of self-assembled indium arsenide (InAs) quantum dots (QDs). These results are significant in the understanding of QD behavior and scientists' ability to utilize QDs in active devices or for information processing. The scientists, from NRL's Materials Science and Technology Division, used a spin-polarized bias current from an iron (Fe) thin film contact and determined the strength of the interaction between spin-polarized electrons in the s, p and d shells. A complete description of this work can be found in Physical Review Letters (28 November 2008).

NRL researchers control the spin of semiconductor quantum dot shell states

Washington, DC | Posted on February 5th, 2009

Semiconductor QDs are nanoscale circular disks of one semiconducting material, typically 3 nm high by 30 nm in diameter, embedded within layers of a second material. Figure 1 shows such a structure, with an atomic force microscope image of the uncovered QDs in figure 2. Semiconductor QDs are attractive for a variety of quantum information processing, electronic and spintronic applications. In spintronic applications, the electron's spin rather than charge is used to store and process information. The International Technology Roadmap for Semiconductors has identified the electron's spin as a new state variable which should be explored as an alternative to the electron's charge for use beyond standard CMOS technology. The QD electronic structure exhibits the s,p,d,f shells characteristic of single atoms, so they are often referred to as "artificial atoms."

The NRL researchers monitor the shell population and spin polarization by measuring the polarized light emitted as a function of the bias current from the Fe contact. In contrast with previous work, they resolve features in the electroluminescence (EL) spectra associated with the individual quantum levels (s-, p-, d-, and f- shells). As the bias current is increased, the shell states fill, and the EL from the QDs exhibits peaks characteristic of the shell energies, as labeled in figure 3.

Intershell exchange strongly modifies the optical polarization observed from that expected for simple models of shell occupation. From a detailed analysis of the EL spectra, the NRL researchers were able to obtain the first experimental measure of the exchange energies between electrons in the s- and p-shells, and between electrons in the p- and d-shells. These energies describe the degree of interaction between these quantum levels.

####

For more information, please click here

Contacts:
Donna McKinney

202-404-3322

Copyright © Naval Research Laboratory

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 News Press

News and information

MIG Takes a Roll-Up-Your-Sleeves Approach with Revamped MEMS/Sensors Technical Event -- MIG welcomes technologists to MEMS Technical Congress, emphasizes working groups and breakout sessions on emerging MEMS & sensors, tech transfer and integration March 6th, 2015

Phenom-World announces the Phenom XL, world’s fastest desktop SEM to handle large samples March 6th, 2015

Air Bearing Stage / Systems Introduced by PI at Photonics West March 6th, 2015

Consistent Scalable Functionalised Graphene Capacity March 5th, 2015

Laboratories

American Chemical Society Presidential Symposia: nanoscience, international chemistry March 5th, 2015

New research could lead to more efficient electrical energy storage March 4th, 2015

Researchers turn unzipped nanotubes into possible alternative for platinum: Aerogel catalyst shows promise for fuel cells March 2nd, 2015

First detailed microscopy evidence of bacteria at the lower size limit of life: Berkeley Lab research provides comprehensive description of ultra-small bacteria February 28th, 2015

Govt.-Legislation/Regulation/Funding/Policy

New research could lead to more efficient electrical energy storage March 4th, 2015

Energy-generating cloth could replace batteries in wearable devices March 4th, 2015

The taming of magnetic vortices: Unified theory for skyrmion-materials March 3rd, 2015

Black phosphorus is new 'wonder material' for improving optical communication March 3rd, 2015

Self Assembly

Nanotubes self-organize and wiggle: Evolution of a nonequilibrium system demonstrates MEPP February 10th, 2015

Engineering self-assembling amyloid fibers January 26th, 2015

Revealed: How bacteria drill into our cells and kill them December 2nd, 2014

Live Images from the Nano-cosmos: Researchers watch layers of football molecules grow November 5th, 2014

Quantum Computing

Strength in numbers: Researchers develop the first-ever quantum device that detects and corrects its own errors March 4th, 2015

Forbidden quantum leaps possible with high-res spectroscopy March 2nd, 2015

Important step towards quantum computing: Metals at atomic scale March 2nd, 2015

Waterloo invention advances quantum computing research: New device, which will be used in labs around the world to develop quantum technologies, produces fragile entangled photons in a more efficient way February 16th, 2015

Discoveries

Enhanced Graphene Components for Next Generation Racing Yacht March 5th, 2015

American Chemical Society Presidential Symposia: nanoscience, international chemistry March 5th, 2015

Strength in numbers: Researchers develop the first-ever quantum device that detects and corrects its own errors March 4th, 2015

New research could lead to more efficient electrical energy storage March 4th, 2015

Announcements

MIG Takes a Roll-Up-Your-Sleeves Approach with Revamped MEMS/Sensors Technical Event -- MIG welcomes technologists to MEMS Technical Congress, emphasizes working groups and breakout sessions on emerging MEMS & sensors, tech transfer and integration March 6th, 2015

Phenom-World announces the Phenom XL, world’s fastest desktop SEM to handle large samples March 6th, 2015

Air Bearing Stage / Systems Introduced by PI at Photonics West March 6th, 2015

Get ready for NanoDays! March 5th, 2015

Quantum Dots/Rods

Optical nanoantennas set the stage for a NEMS lab-on-a-chip revolution February 24th, 2015

QD Vision Named Edison Award Finalist for Innovative Color IQ™ Quantum Dot Technology February 23rd, 2015

Ocean Optics Names Winner of 2015 Young Investigator Award: Cash prize and grant awarded during SPIE BiOS/Photonics West 2015 conference February 21st, 2015

Rediscovering spontaneous light emission: Berkeley researchers develop optical antenna for LEDs February 3rd, 2015

Quantum nanoscience

Important step towards quantum computing: Metals at atomic scale March 2nd, 2015

Quantum many-body systems on the way back to equilibrium: Advances in experimental and theoretical physics enable a deeper understanding of the dynamics and properties of quantum many-body systems February 25th, 2015

Quantum research past, present and future for discussion at AAAS February 16th, 2015

Exotic states materialize with supercomputers February 12th, 2015

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




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE