Nanotechnology Now

Our NanoNews Digest Sponsors





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

March 2016; 6th Int'l Conference on Nanostructures in Iran July 29th, 2015

Non-Enzyme Sensor Determines Level of Blood Sugar July 29th, 2015

Flexible Future of Point-of-Care Disease Diagnostic July 29th, 2015

Meet the high-performance single-molecule diode: Major milestone in molecular electronics scored by Berkeley Lab and Columbia University team July 29th, 2015

Detecting small metallic contaminants in food via magnetization: A practical metallic-contaminant detecting system using three high-Tc RF superconducting quantum interference devices (SQUIDs) July 29th, 2015

Laboratories

Meet the high-performance single-molecule diode: Major milestone in molecular electronics scored by Berkeley Lab and Columbia University team July 29th, 2015

New computer model could explain how simple molecules took first step toward life: Two Brookhaven researchers developed theoretical model to explain the origins of self-replicating molecules July 28th, 2015

Short wavelength plasmons observed in nanotubes: Berkeley Lab researchers create Ludinger liquid plasmons in metallic SWNTs July 28th, 2015

Govt.-Legislation/Regulation/Funding/Policy

Pakistani Students Who Survived Terror Attack to Attend Weeklong “NanoDiscovery Institute” at SUNY Poly CNSE in Albany July 29th, 2015

Meet the high-performance single-molecule diode: Major milestone in molecular electronics scored by Berkeley Lab and Columbia University team July 29th, 2015

New computer model could explain how simple molecules took first step toward life: Two Brookhaven researchers developed theoretical model to explain the origins of self-replicating molecules July 28th, 2015

Short wavelength plasmons observed in nanotubes: Berkeley Lab researchers create Ludinger liquid plasmons in metallic SWNTs July 28th, 2015

Self Assembly

New computer model could explain how simple molecules took first step toward life: Two Brookhaven researchers developed theoretical model to explain the origins of self-replicating molecules July 28th, 2015

Spintronics: Molecules stabilizing magnetism: Organic molecules fixing the magnetic orientation of a cobalt surface/ building block for a compact and low-cost storage technology/ publication in Nature Materials July 25th, 2015

Imec introduces self-assembled monomolecular organic films to seal ultra-porous low- k materials: Method prevents leakage of barrier precursors during the interconnect metallization scheme July 15th, 2015

Clay sheets stack to form proton conductors: Model system demonstrates a new material property emerging from the assembly of nanoscale building blocks July 13th, 2015

Quantum Computing

Quantum networks: Back and forth are not equal distances! July 28th, 2015

The quantum middle man July 2nd, 2015

Freezing single atoms to absolute zero with microwaves brings quantum technology closer: Atoms frozen to absolute zero using microwaves July 2nd, 2015

Producing spin-entangled electrons July 2nd, 2015

Discoveries

Non-Enzyme Sensor Determines Level of Blood Sugar July 29th, 2015

Flexible Future of Point-of-Care Disease Diagnostic July 29th, 2015

Meet the high-performance single-molecule diode: Major milestone in molecular electronics scored by Berkeley Lab and Columbia University team July 29th, 2015

Detecting small metallic contaminants in food via magnetization: A practical metallic-contaminant detecting system using three high-Tc RF superconducting quantum interference devices (SQUIDs) July 29th, 2015

Announcements

Non-Enzyme Sensor Determines Level of Blood Sugar July 29th, 2015

Flexible Future of Point-of-Care Disease Diagnostic July 29th, 2015

Meet the high-performance single-molecule diode: Major milestone in molecular electronics scored by Berkeley Lab and Columbia University team July 29th, 2015

Detecting small metallic contaminants in food via magnetization: A practical metallic-contaminant detecting system using three high-Tc RF superconducting quantum interference devices (SQUIDs) July 29th, 2015

Quantum Dots/Rods

Quantum networks: Back and forth are not equal distances! July 28th, 2015

Superfast fluorescence sets new speed record: Plasmonic device has speed and efficiency to serve optical computers July 27th, 2015

Engineered hybrid crystal opens new frontiers for high-efficiency lighting: University of Toronto researchers successfully combine 2 different materials to create new hyper-efficient light-emitting crystal July 16th, 2015

Down to the quantum dot: Jülich researchers develop ultrahigh-resolution 3-D microscopy technique for electric fields July 7th, 2015

Quantum nanoscience

Detecting small metallic contaminants in food via magnetization: A practical metallic-contaminant detecting system using three high-Tc RF superconducting quantum interference devices (SQUIDs) July 29th, 2015

Drawing a line between quantum and classical world: Bell's Inequality fails as a test of the boundary July 21st, 2015

World first: Significant development in the understanding of macroscopic quantum behavior: Researchers from Polytechnique Montréal and Imperial College London demonstrate the wavelike quantum behavior of a polariton condensate on a macroscopic scale and at room temperature July 14th, 2015

The quantum physics of artificial light harvesting: How molecular vibrations make photosynthesis efficient July 13th, 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