Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Nano-hillocks: Of mountains and craters

Following bombardment with highly charged ions, nano-hillocks have formed in an area of localized melting. Atomic force microscope image.
Picture: HZDR
Following bombardment with highly charged ions, nano-hillocks have formed in an area of localized melting. Atomic force microscope image.

Picture: HZDR

Abstract:
n the field of nanotechnology, electrically-charged particles are frequently used as tools for surface modification. Researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and the TU Vienna were at last able to reconcile important issues concerning the effects of highly charged ions on surfaces.

Nano-hillocks: Of mountains and craters

Dresden, Germany | Posted on October 1st, 2012

Ion beams have been used for some time now for surface modification as ions are capable of carrying such high energies that a single particle alone can induce drastic changes to the surface under bombardment. Following careful examination, an international team of researchers was at last able to shed light on the reasons why sometimes craters and other times hillocks are forming as a result of this process. Their findings have recently been published in the scientific journal, Physical Review Letters.
Charge instead of speed

"If the goal is to deposit a maximum amount of energy on a tiny spot on the surface, it is of comparatively little use to simply bombard the surface with fast atoms," explains Prof. Friedrich Aumayr of the TU Vienna's Institute of Applied Physics. "Fast particles penetrate deep into the material thereby depositing their energy over a wide range." If, however, you first strip a large number of electrons from individual atoms and then allow these highly charged ions to collide with the material surface, the effects you get are quite dramatic as the energy that was previously required to ionize the atoms is now being released within a very small area of a few nanometers in diameter, and within an ultrashort time.

This can lead to melting of a very small volume of the material, loss of its orderly atomic structure, and, finally, its expansion. The large number of electronic excitations that result from the ion's interactions with the surface has a strong impact on the material and ultimately leads to the atoms being bumped out of position. The end-result is nano-hillock formation - the appearance of tiny protrusions on the material's surface. If the energy required to initiate melting of the material is insufficient, small holes or defects will form on or below the surface instead.

Elaborate experiments at the HZDR facility for highly charged ions were just as important to obtaining a detailed picture of the processes that take place at the material's surface as were computer simulations and extensive theoretical work. "At our new HZDR facility, we have the capabilities for deliberately forming nano-hillocks and nano-craters on surfaces. In close collaboration with the groups of our colleagues Friedrich Aumayr and Joachim Burgdörfer at the TU Vienna we succeeded to grasp the underlying physical mechanisms in more detail", explains Dr. Stefan Facsko. Egyptian physicist Dr. Ayman El-Said, who spent two years as a Humboldt Foundation fellow conducting research at HZDR, made substantial contributions to the current body of research in this field.
Assumptions confirmed

The scientists are calling their results the missing important piece of the puzzle to help them understand the interaction of highly charged ions with surfaces. By subjecting the sample to an acid treatment following ion bombardment, they are able to document the extent to which a surface is modified at given energies. The formation of nano-hillocks depends to a large extent on the ion beams' charge state and to a lesser extent on their velocity. The formation of craters, on the other hand, is dependent upon both the charge state and the kinetic energy of the ions. The Vienna and Dresden researchers had long suspected this and were now at last able to produce the necessary evidence obtained from their experiments conducted at the HZDR.

####

For more information, please click here

Contacts:
Dr. René Heller
Institute of Ion Beam Physics and Materials Research at HZDR
Phone: +49 351 260-3617


Dr. Christine Bohnet
Press Officer

49-351-260-2450
oder +49 160 969 288 56

Copyright © Helmholtz Association of German Research Centres

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

Publication

Related News Press

News and information

Atomic Force Microscopes from Asylum Research Guide the Development of Thin Film Deposition and Etch Processes September 2nd, 2015

For 2-D boron, it's all about that base: Rice University theorists show flat boron form would depend on metal substrates September 2nd, 2015

Silk bio-ink could help advance tissue engineering with 3-D printers September 2nd, 2015

Phagraphene, a 'relative' of graphene, discovered September 2nd, 2015

Physics

Hot electrons point the way to perfect light absorption: Physicists study how to achieve perfect absorption of light with the help of rough ultrathin films September 1st, 2015

Scientists 'squeeze' light one particle at a time: A team of scientists have measured a bizarre effect in quantum physics, in which individual particles of light are said to have been 'squeezed' -- an achievement which at least one textbook had written off as hopeless September 1st, 2015

Using ultrathin sheets to discover new class of wrapped shapes: UMass Amherst materials researchers describe a new regime of wrapped shapes August 31st, 2015

Seeing quantum motion August 30th, 2015

Discoveries

For 2-D boron, it's all about that base: Rice University theorists show flat boron form would depend on metal substrates September 2nd, 2015

Silk bio-ink could help advance tissue engineering with 3-D printers September 2nd, 2015

Phagraphene, a 'relative' of graphene, discovered September 2nd, 2015

A marine creature's magic trick explained: Crystal structures on the sea sapphire's back appear differently depending on the angle of reflection September 2nd, 2015

Announcements

For 2-D boron, it's all about that base: Rice University theorists show flat boron form would depend on metal substrates September 2nd, 2015

Silk bio-ink could help advance tissue engineering with 3-D printers September 2nd, 2015

Phagraphene, a 'relative' of graphene, discovered September 2nd, 2015

A marine creature's magic trick explained: Crystal structures on the sea sapphire's back appear differently depending on the angle of reflection September 2nd, 2015

Tools

Oxford Instruments’ Triton Cryofree dilution refrigerator selected by Oxford University for developing scalable quantum nanodevices September 2nd, 2015

JEOL Introduces New Best-in-Class Field Emission SEM September 2nd, 2015

Atomic Force Microscopes from Asylum Research Guide the Development of Thin Film Deposition and Etch Processes September 2nd, 2015

Nanolab Technologies LEAPS Forward with High-Performance Analysis Services to the World: Nanolab Orders Advanced Local Electrode Atom Probe (LEAP®) Microscope from CAMECA Unit of AMETEK Materials Analysis Division August 27th, 2015

Research partnerships

Sustainable nanotechnology center September 1st, 2015

$200K Awarded to Develop In Vitro Lung Test for Toxicity of Inhaled Nanomaterials: In Vitro Lung Test Designed to Protect Human Health and Replace Animal Testing September 1st, 2015

Hot electrons point the way to perfect light absorption: Physicists study how to achieve perfect absorption of light with the help of rough ultrathin films September 1st, 2015

Nanocatalysts improve processes for the petrochemical industry August 28th, 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







Car Brands
Buy website traffic