Nanotechnologists from Penn collaborate to form near-frictionless diamond material

February 25, 2010

PHILADELPHIA -- Researchers at the University of Pennsylvania, the University of Wisconsin-Madison and IBM Research-Zürich have fabricated an ultra sharp, diamond-like carbon tip possessing such high strength that it is 3,000 times more wear-resistant at the nanoscale than silicon.

The end result is a diamond-like carbon material mass-produced at the nanoscale that doesn't wear. The new nano-sized tip, researchers say, wears away at the rate of one atom per micrometer of sliding on a substrate of silicon dioxide, much lower than that for a silicon oxide tip which represents the current state-of-the-art. Consisting of carbon, hydrogen, silicon and oxygen molded into the shape of a nano-sized tip and integrated on the end of a silicon microcantilever for use in atomic force microscopy, the material has technological implications for atomic imaging, probe-based data storage and as emerging applications such as nanolithography, nanometrology and nanomanufacturing.

The importance of the discovery lies not just in its size and resistance to wear but also in the hard substrate against which it was shown to perform well when in sliding contact: silicon dioxide. Because silicon -- used in almost all integrated circuit devices -- oxidizes in atmosphere forming a thin layer of its oxide, this system is the most relevant for nanolithography, nanometrology and nanomanufacturing applications.

Probe-based technologies are expected to play a dominant role in many such technologies; however, poor wear performance of many materials when slid against silicon oxide, including silicon oxide itself, has severely limited usefulness to the laboratory.

Researchers built the material from the ground up, rather than coating a nanoscale tip with wear-resistant materials. The collaboration used a molding technique to fabricate monolithic tips on standard silicon microcantilevers. A bulk processing technique that has the potential to scale up for commercial manufacturing is available.

Robert Carpick, professor in the Department of Mechanical Engineering and Applied Mechanics at Penn, and his research group had previously shown that carbon-based thin films, including diamond-like carbon, had low friction and wear at the nanoscale; however, it has been difficult to fabricate nanoscale structures made out of diamond-like carbon until now.

Understanding friction and wear at the nanoscale is important for many applications that involve nanoscale components sliding on a surface.

"It is not clear that materials that are wear-resistant at the macroscale exhibit the same property at the nanoscale," lead author Harish Bhaskaran, who was a postdoctoral research at IBM during the study, said.

Defects, cracks and other phenomena that influence material strength and wear at macroscopic scales are less important at the nanoscale, which is why nanowires can, for example, show higher strengths than bulk samples.
-end-
The study, published in the current edition of the journal Nature Nanotechnology, was conducted collaboratively by Carpick and postdoctoral researcher Papot Jaroenapibal of the Department of Mechanical Engineering and Applied Mechanics in Penn's School of Engineering and Applied Science; Bhaskaran, Bernd Gotsmann, Abu Sebastian, Ute Drechsler, Mark A. Lantz and Michel Despont of IBM Research-Zürich; and Yun Chen and Kumar Sridharan of the University of Wisconsin. Jaroenapibal currently works at Khon Kaen University in Thailand, and Bhaskaran currently works at Yale University.

Research was funded by a European Commission grant and the Nano/Bio Interface Center of the University of Pennsylvania through the National Science Foundation.

University of Pennsylvania

Related Nanoscale Articles from Brightsurf:

Nanoscale machines convert light into work
Researchers have developed a tiny new machine that converts laser light into work.

Discovery will allow more sophisticated work at nanoscale
The movement of fluids through small capillaries and channels is crucial for processes ranging from blood flow through the brain to power generation and electronic cooling systems, but that movement often stops when the channel is smaller than 10 nanometers.

Valley-Hall nanoscale lasers
Topological photonics allows the creation of new states of light.

Dynamics of DNA replication revealed at the nanoscale
Using super-resolution technology a University of Technology Sydney led team has directly visualised the process of DNA replication in single human cells.

House cleaning on the nanoscale
A team of scientists at Friedrich-Alexander Universität Erlangen-Nürnberg (FAU) has developed a novel mechanical cleaning method for surfaces on the nanoscale.

As electronics shrink to nanoscale, will they still be good as gold?
As circuit interconnects shrink to nanoscale, will the pressure caused by thermal expansion when current flows through wires cause gold to behave more like a liquid than a solid -- making nanoelectronics unreliable?

A joint venture at the nanoscale
Scientists at Argonne National Laboratory report fabricating and testing a superconducting nanowire device applicable to high-speed photon counting.

Bending diamond at the nanoscale
A team of Australian scientists has discovered diamond can be bent and deformed, at the nanoscale at least.

Creating a nanoscale on-off switch for heat
Researchers create a polymer thermal regulator that can quickly transform from a conductor to an insulator, and back again.

Magnetic tuning at the nanoscale
Physicists from the German research center Helmholtz-Zentrum Dresden-Rossendorf (HZDR) are working to produce engineered magnetic nanostructures and to tailor material properties at the nanoscale.

Read More: Nanoscale News and Nanoscale Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.