Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nanoshaping method points to future manufacturing technology

12.12.2014

A new method that creates large-area patterns of three-dimensional nanoshapes from metal sheets represents a potential manufacturing system to inexpensively mass produce innovations such as "plasmonic metamaterials" for advanced technologies.

The metamaterials have engineered surfaces that contain features, patterns or elements on the scale of nanometers that enable unprecedented control of light and could bring innovations such as high-speed electronics, advanced sensors and solar cells.

The new method, called laser shock imprinting, creates shapes out of the crystalline forms of metals, potentially giving them ideal mechanical and optical properties using a bench-top system capable of mass producing the shapes inexpensively

Findings are detailed in a research paper appearing Friday (Dec. 12) in the journal Science. The paper is authored by researchers from Purdue University, Harvard University, Madrid Institute for Advanced Studies, and the University of California, San Diego. The research is led by Gary Cheng, an associate professor of industrial engineering at Purdue.

The shapes, which include nanopyramids, gears, bars, grooves and a fishnet pattern, are too small to be seen without specialized imaging instruments and are thousands of times thinner than the width of a human hair. The researchers used their technique to stamp nanoshapes out of titanium, aluminum, copper, gold and silver.

A key benefit of the shock-induced forming is sharply defined corners and vertical features, or high-fidelity structures.

"These nanoshapes also have extremely smooth surfaces, which is potentially very advantageous for commercial applications," Cheng said. "Traditionally it has been really difficult to deform a crystalline material into a nanomold much smaller than the grain size of starting materials, and due to the size effects the materials are super-strong when grain size has to be reduced to very small sizes. Therefore, it is very challenging to generate metal flow into nanomolds with high-fidelity 3-D shaping."

The researchers also created hybrid structures that combine metal with graphene, an ultrathin sheet of carbon promising for various technologies. Such a hybrid material could enhance the plasmonic effect and bring "metamaterial perfect absorbers," or MPAs, which have potential applications in optoelectronics and wireless communications.

"We can generate nanopatterns on metal-graphene hybrid materials, which opens new ways to pattern 2-D crystals," Cheng said.

The technique works by using a pulsed laser to generate "high strain rate" imprinting of metals into the nanomold.

"We start with a metal thin film, and we can deform it into 3-D nanoshapes patterned over large areas," Cheng said. "What is more interesting is that the resulting 3-D nanostructures are still crystalline after the imprinting process, which provides good electromagnetic and optical properties."

Whereas other researchers have created nanoshapes out of relatively soft or amorphous materials, the new research shows how to create nanoshapes out of hard and crystalline metals.

The silicon nanomolds were fabricated at the Birck Nanotechnology Center in Purdue's Discovery Park by a research group led by Minghao Qi, an associate professor of electrical and computer engineering.

"It is counter-intuitive to use silicon for molds because it is a pretty brittle material compared to metals," Qi said. "However, after we deposit an ultrathin layer of aluminum oxide on the nanomolds, it performs extremely well for this purpose. The nanomolds could be reused many times without obvious damage. Part of the reason is that although the strain rate is very high, the shock pressure applied is only about 1-2 gigapascals."

The shapes were shown to have an "aspect ratio" as high as 5, meaning the height is five times greater than the width, an important feature for the performance of plasmonic metamaterials.

"It is a very challenging task from a fabrication point of view to create ultra-smooth, high-fidelity nanostructures," Qi says. "Normally when metals recrystallize they form grains and that makes them more or less rough. Previous trials to form metal nanostructures have had to resort to very high pressure imprinting of crystalline metals or imprinting amorphous metal, which either yields high roughness in crystalline metals or smooth surfaces in amorphous metals but very high electrical resistance. For potential applications in nanoelectronics, optoelectronics and plasmonics you want properties such as high precision, low electromagnetic loss, high electrical and thermal conductivity. You also want it to be very high fidelity in terms of the pattern, sharp corners, vertical sidewalls, and those are very difficult to obtain. Before Gary's breakthrough, I thought it unlikely to achieve all of the good qualities together."

The paper was authored by Purdue doctoral students Huang Gao, Yaowu Hu, Ji Li, and Yingling Yang; researcher Ramses V. Martinez from Harvard and Madrid Institute for Advanced Studies; Purdue research assistant professor Yi Xuan, Purdue research associate Chunyu Li; Jian Luo, a professor at the University of California, San Diego; Qi and Cheng.

Future research may focus on using the technique to create a roll-to-roll manufacturing system, which is used in many industries including paper and sheet-metal production and may be important for new applications such as flexible electronics and solar cells.

The work was supported by the National Science Foundation, National Institutes of Health, Defense Threat Reduction Agency, Office of Naval Research and the National Research Council.

Writer: Emil Venere, 765-494-4709, venere@purdue.edu

Sources: Gary J. Cheng, 765-494-5436, gjcheng@purdue.edu

Minghao Qi, 765-494-3646, mqi@purdue.edu

Note to Journalists: A copy of the article is available by contacting the Science Press Package team at 202-326-6440, scipak@aaas.org

ABSTRACT

Large Scale Nanoshaping of Ultrasmooth 3D Crystalline Metallic Structures

Huang Gao1,3,*, Yaowu Hu1,3,*, Yi Xuan2,3,*, Ji Li1,3, Yingling Yang1,3, Ramses V. Martinez4,5, Chunyu Li3,6, Jian Luo7, Minghao Qi2,3, Gary J. Cheng1,3,8†

1 School of Industrial Engineering, Purdue University

2 School of Electrical and Computer Engineering, Purdue University

3 Birck Nanotechnology Center, Purdue University

4 Department of Chemistry and Chemical Biology, Harvard University

5 Madrid Institute for Advanced Studies, IMDEA Nanoscience, Ciudad Universitaria de Cantoblanco

6 School of Materials Engineering, Purdue University

7 Department of NanoEngineering, University of California San Diego

8 School of Mechanical Engineering, Purdue University

* These authors contributed equally to this work

† Corresponding author. E-mail: gjcheng@purdue.edu

This paper reports a low-cost, high-throughput, benchtop method that enables thin layers of metal to be shaped with nanoscale precision by generating ultrahigh-strain-rate deformations. Laser shock imprinting can create 3D crystalline metallic structures as small as 10 nm with ultrasmooth surfaces at ambient conditions. This technique enables the successful fabrications of large-area, uniform nanopatterns with aspect ratios as high as 5 for plasmonic and sensing applications, as well as mechanically strengthened nanostructures and metal-graphene hybrid

Emil Venere | EurekAlert!
Further information:
http://www.purdue.edu/newsroom/releases/2014/Q4/nanoshaping-method-points-to-future-manufacturing-technology.html

More articles from Process Engineering:

nachricht Dresdner scientists print tomorrow’s world
08.02.2017 | Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS

nachricht New technology for mass-production of complex molded composite components
23.01.2017 | Evonik Industries AG

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short

23.03.2017 | Life Sciences

Researchers use light to remotely control curvature of plastics

23.03.2017 | Power and Electrical Engineering

Sea ice extent sinks to record lows at both poles

23.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>