Navigation Links
How ion bombardment reshapes metal surfaces
Date:5/22/2012

PROVIDENCE, R.I. [Brown University] To modify a metal surface at the scale of atoms and molecules for instance to refine the wiring in computer chips or the reflective silver in optical components manufacturers shower it with ions. While the process may seem high-tech and precise, the technique has been limited by the lack of understanding of the underlying physics. In a new study, Brown University engineers modeled noble gas ion bombardments with unprecedented richness, providing long-sought insights into how it works.

"Surface patterns and stresses caused by ion beam bombardments have been extensively studied experimentally but could not be predicted accurately so far," said Kyung-Suk Kim, professor of engineering at Brown and co-author of the study published May 23 in the Proceedings of the Royal Society A. "The new discovery is expected to provide predictive design capability for controlling the surface patterns and stresses in nanotechnology products."

The improved understanding could open the door to new technologies, Kim said, such as new approaches to make flexible electronics, biocompatible surfaces for medical devices, and more damage-tolerant and radiation-resistant surfaces. The research applies to so-called "FCC" metals such as copper, silver, gold, nickel, and aluminum. Those metals are crystals made up of cubic arrangements of atoms with one at each corner and one in each cube-face center.

Scientists have been trying to explain the complicated process for decades, and more recently they have begun to try modeling it on computers. Kim said the analysis of the Brown team, including lead author and postdoctoral scholar Sang-Pil Kim, was more sophisticated than previous attempts that focused on a single bombardment event and only isolated point defects within the metal substrate.

"In this work, for the first time, we investigate collective behavior of those defects during ion bombardments in terms of ion-substrate combinations," Kyung-Suk Kim said.

The new model revealed how ion bombardments can set three main mechanisms into motion in a matter of trillionths of a second. The researchers dubbed the mechanisms "dual layer formation," "subway-glide mode growth," and "adatom island eruption." They are a consequence of how the incoming ions melt the metal and then how it resolidifies with the ions occasionally trapped inside.

When ions hit the metal surface, they penetrate it, knocking away nearby atoms like billiard balls in a process that is akin, at the atomic level, to melting. But rather than merely rolling away, the atoms are more like magnetic billiard balls in that they come back together, or resolidify, albeit in a different order.

Some atoms have been shifted out of place. There are some vacancies in the crystal nearer to the surface, and the atoms there pull together across the empty space, that creates a layer with more tension. Beneath that is a layer with more atoms that have been knocked into it. That crowding of atoms creates compression. Hence there are now two layers with different levels of compression and tension.This "dual layer formation" is the precursor to the "subway-glide mode growth" and "adatom island eruption".

A hallmark of materials that have been bombarded with ions is that they sometimes produce a pattern of material that seems to have popped up out of the original surface. Previously, Kyung-Suk Kim said, scientists thought displaced atoms would individually just bob back up to the surface like fish killed in an underwater explosion. But what the team's models show is that these molecular islands are formed by whole clusters of displaced atoms that bond together and appear to glide back up to the surface.

"The process is analogous to people getting on a subway train at suburban stations, and they all come out together to the surface once the train arrives at a downtown station during the morning rush hour," Kyung-Suk Kim said.

The mechanisms, while offering a new explanation for the effects of ion bombardment, are just the beginning of this research.

"As a next step, I will develop prediction models for nanopattern evolution during ion bombardment which can guide the nanomanufacturing processes," Sang-Pil Kim said. "This research will also be expanded to other applications such as soft- or hard-materials under extreme conditions."


'/>"/>
Contact: David Orenstein
david_orenstein@brown.edu
401-863-1862
Brown University
Source:Eurekalert  

Related biology technology :

1. Making microscopic machines using metallic glass
2. In metallic glasses, researchers find a few new atomic structures
3. Metal nanoparticles shine with customizable color
4. ORNL experiments prove nanoscale metallic conductivity in ferroelectrics
5. Hydrogen released to fuel cell more quickly when stored in metal nanoparticles
6. A new discovery paves the way for using super strong nanostructured metals in cars
7. Natural gas produced from fine milling of precious metals
8. Heavy metals open path to high temperature nanomagnets
9. Templated growth technique produces graphene nanoribbons with metallic properties
10. Liquid metal key to simpler creation of electrodes for microfluidic devices
11. Leading Scientific Laboratory Offers New Methods for Metals Testing
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
How ion bombardment reshapes metal surfaces
(Date:2/11/2016)...  Bioethics International, a not-for-profit organization focused on the ethics ... made accessible to patients around the world, today announced that ... publication of the Good Pharma Scorecard an ... as one of BMJ Open ,s ,Most Popular Articles, ... most frequently read. Ed Sucksmith , assistant editor ...
(Date:2/11/2016)... Florida , February 11, 2016 ... PositiveID Corporation ("PositiveID" or "Company") (OTCQB: PSID), a ... announced today that its Thermomedics subsidiary, which markets ... on its growth plan in January 2016, including ... distributors, increasing sequential monthly sales growth, and establishing ...
(Date:2/10/2016)... - BioAmber Inc. (NYSE: BIOA ), a leader ... & Co. Ltd., its partner in the ... an additional CDN$25 million in the joint venture for ... to 40%.  Mitsui will also play a stronger role ... Sarnia , providing dedicated resources alongside BioAmber,s ...
(Date:2/10/2016)... (PRWEB) , ... February 10, ... ... REGN) today announced that it has joined the Human Vaccines Project, a ... infectious diseases and cancer. , The Human Vaccines Project brings together ...
Breaking Biology Technology:
(Date:2/2/2016)... NEW YORK , Feb. 2, 2016 /PRNewswire/ ... Potentials of that Rising Market Are you ... new analysis forecasts revenues for checkpoint inhibitors. Visiongain,s ... world market, submarket, product and national level. ... Instead discover what progress, opportunities and revenues those ...
(Date:2/2/2016)... 2016   Parabon NanoLabs (Parabon) announced ... Research Office and the Defense Forensics and Biometrics ... the company,s Snapshot Kinship Inference software ... generally, defense-related DNA forensics.  Although Snapshot is best ... and ancestry from DNA evidence), it also has ...
(Date:2/1/2016)... Canada , February 1, 2016 ... technological advancements to drive global touchfree intuitive gesture control ... --> Rising sales of consumer electronics coupled ... gesture control market size through ... consumer electronics coupled with new technological advancements to drive ...
Breaking Biology News(10 mins):