. 24/7 Space News .
NANO TECH
Whisper gallery modes in Silicon nanocones intensify luminescence
by Staff Writers
Berlin, Germany (SPX) Dec 04, 2015


The diameter of the nanocolumns is 570 nm. By comparison, the nanocones taper from their upper diameter of 940 nm down to 360 nm at their base. Image courtesy MPL. For a larger version of this image please go here.

Silicon is a conventional material for computer chips and solar cells. However, even though the properties of silicon are well known, nanostructures still offer up surprises. A team headed by Prof. Silke Christiansen at the HZB Institute of Nanoarchitectures for Energy Conversion together with the Max Planck Institute for the Science of Light (MPL) has shown for the first time how light behaves in a silicon nanocone.

Their numerical simulations and experiments now demonstrate why this tapered geometry is able to emit optically excited luminescence a great deal better that comparably sized nanocolumns. "The cones function like arrays of tiny whispering galleries - not for sound, but rather for light", explains Sebastian Schmitt, first author.

Strong luminescence in nanoconesx
Schmitt and his colleague George Sarau irradiated individual silicon nanocolumns and nanocones using red laser light (660 nanometres) and measured the radiation that was subsequently emitted as luminescence by the sample. It is known that luminescence in silicon (without any nanostructuring) is normally very low because excited electrons hardly recombine radiatively in this material (indirect band gap).

In contrast, the nanostructures convert a much greater portion of the incident light into electromagnetic radiation in the near-infrared region. This effect in nanocones is 200 times stronger than in nanocolumns. "This is the highest luminescence gain ever measured in a silicon structure", says Schmitt.

Modelling demonstrates whisper gallery modes
The team can also explain why this is. The propagation of electromagnetic waves in various geometries of silicon nanowires can be calculated using numerical modelling. Because the diameter of the nanocone changes with height, there are several levels at which the infrared light is constructively superposed to form standing waves.

This amplification facilitates increased excitation of electrons and thus the release of luminescence. This phenomenon is known as the Purcell Effect in the field. If a light source is located in an optical resonator, spontaneous emission of light increases. The nanocones act as outstanding resonators, like optical whisper galleries for light.

Design rules for novel devices
"These types of nanostructures made of individual cones are not difficult to fabricate", explains Schmitt. They would be easily integrated as new components into predominant CMOS semiconductor fabrication techniques used for diodes, optoelectronic switches, and optical sensors, for example. These structures could even produce laser light in conjunction with a suitable optically active medium, the physicist surmises.

"We can derive simple design rules for semiconductor nanostructures with this kind of knowledge to exert control over the number and wavelengths of hosted modes and thereby control the luminescence", says Christiansen.

The results have been published in the renowned journal Scientific Reports, DOI: 10.1038/srep17089 "Observation of strongly enhanced photoluminescence from inverted cone-shaped silicon nanostuctures" Sebastian W. Schmitt, George Sarau and Silke Christiansen.


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only


.


Related Links
Helmholtz-Zentrum Berlin fur Materialien und Energie
Nano Technology News From SpaceMart.com
Computer Chip Architecture, Technology and Manufacture






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
NANO TECH
Electric fields remove nanoparticles from blood with ease
San Diego CA (SPX) Dec 01, 2015
Engineers at the University of California, San Diego developed a new technology that uses an oscillating electric field to easily and quickly isolate drug-delivery nanoparticles from blood. The technology could serve as a general tool to separate and recover nanoparticles from other complex fluids for medical, environmental, and industrial applications. Nanoparticles, which are generally o ... read more


NANO TECH
Gaia's sensors scan a lunar transit

SwRI scientists explain why moon rocks contain fewer volatiles than Earth's

All-female Russian crew starts Moon mission test

Russian moon mission would need 4 Angara-A5V launches

NANO TECH
Mars Mission Team Addressing Vacuum Leak on Key Science Instrument

Letter to Mars? Royal Mail works it out for British boy, 5

European payload selected for ExoMars 2018 surface platform

ExoMars has historical, practical significance for Russia, Europe

NANO TECH
A Year After Maiden Voyage, Orion Progress Continues

NASA's Work to Understand Climate: A Global Perspective

Australia seeks 'ideas boom' with tax breaks, visa boosts

Orion's power system to be put to the test

NANO TECH
China's indigenous SatNav performing well after tests

China launches Yaogan-29 remote sensing satellite

China's scientific satellites to enter uncharted territory

China to launch Dark Matter Satellite in mid-December

NANO TECH
Getting Into the Flow on the ISS

Orbital to fly first space cargo mission since 2014 explosion

Russian-US Space Collaboration Intact Despite Chill in Bilateral Ties

ISS EarthKAM ready for student imaging request

NANO TECH
45th Space Wing supports NASA's Orbital ATK CRS-4 launch

Virgin Galactic Welcomes 'Cosmic Girl' To Fleet Of Space Access Vehicles

Orbital cargo ship blasts off toward space station

Aerojet Rocketdyne completes AJ60 solid booster for Atlas V launcher

NANO TECH
What kinds of stars form rocky planets

Half of Kepler's giant exoplanet candidates are false positives

Exiled exoplanet likely kicked out of star's neighborhood

Neptune-size exoplanet around a red dwarf star

NANO TECH
In-Space Manufacturing Prototype

Space Debris - A Growth Industry?

Russia's Kanopus-ST Research Satellite Deorbited, Heading to Earth

A new form of real gold, almost as light as air









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.