Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



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

Virginia Tech physicists propose path to faster, more flexible robots: Virginia Tech physicists revealed a microscopic phenomenon that could greatly improve the performance of soft devices, such as agile flexible robots or microscopic capsules for drug delivery May 17th, 2024

Gene therapy relieves back pain, repairs damaged disc in mice: Study suggests nanocarriers loaded with DNA could replace opioids May 17th, 2024

Shedding light on perovskite hydrides using a new deposition technique: Researchers develop a methodology to grow single-crystal perovskite hydrides, enabling accurate hydride conductivity measurements May 17th, 2024

Physics

Finding quantum order in chaos May 17th, 2024

International research team uses wavefunction matching to solve quantum many-body problems: New approach makes calculations with realistic interactions possible May 17th, 2024

Discoveries

Virginia Tech physicists propose path to faster, more flexible robots: Virginia Tech physicists revealed a microscopic phenomenon that could greatly improve the performance of soft devices, such as agile flexible robots or microscopic capsules for drug delivery May 17th, 2024

Diamond glitter: A play of colors with artificial DNA crystals May 17th, 2024

Finding quantum order in chaos May 17th, 2024

Advances in priming B cell immunity against HIV pave the way to future HIV vaccines, shows quartet of new studies May 17th, 2024

Announcements

Virginia Tech physicists propose path to faster, more flexible robots: Virginia Tech physicists revealed a microscopic phenomenon that could greatly improve the performance of soft devices, such as agile flexible robots or microscopic capsules for drug delivery May 17th, 2024

Diamond glitter: A play of colors with artificial DNA crystals May 17th, 2024

Finding quantum order in chaos May 17th, 2024

Oscillating paramagnetic Meissner effect and Berezinskii-Kosterlitz-Thouless transition in cuprate superconductor May 17th, 2024

Tools

First direct imaging of small noble gas clusters at room temperature: Novel opportunities in quantum technology and condensed matter physics opened by noble gas atoms confined between graphene layers January 12th, 2024

New laser setup probes metamaterial structures with ultrafast pulses: The technique could speed up the development of acoustic lenses, impact-resistant films, and other futuristic materials November 17th, 2023

Ferroelectrically modulate the Fermi level of graphene oxide to enhance SERS response November 3rd, 2023

The USTC realizes In situ electron paramagnetic resonance spectroscopy using single nanodiamond sensors November 3rd, 2023

Research partnerships

Gene therapy relieves back pain, repairs damaged disc in mice: Study suggests nanocarriers loaded with DNA could replace opioids May 17th, 2024

Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024

Researchers’ approach may protect quantum computers from attacks March 8th, 2024

How surface roughness influences the adhesion of soft materials: Research team discovers universal mechanism that leads to adhesion hysteresis in soft materials March 8th, 2024

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