Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > A new way to build nanostructures: Combining top-down and bottom-up approaches, new low-cost method could be a boon to research with a variety of applications.

The new 3D nanofabrication method makes it possible to manufacture complex multi-layered solids all in one step. In this example, seen in these Scanning Electron Microscope images, a view from above (at top) shows alternating layers containing round holes and long bars. As seen from the side (lower image), the alternating shapes repeat through several layers.
Image: Chih-Hao Chang
The new 3D nanofabrication method makes it possible to manufacture complex multi-layered solids all in one step. In this example, seen in these Scanning Electron Microscope images, a view from above (at top) shows alternating layers containing round holes and long bars. As seen from the side (lower image), the alternating shapes repeat through several layers.
Image: Chih-Hao Chang

Abstract:
The making of three-dimensional nanostructured materials — ones that have distinctive shapes and structures at scales of a few billionths of a meter — has become a fertile area of research, producing materials that are useful for electronics, photonics, phononics and biomedical devices. But the methods of making such materials have been limited in the 3-D complexity they can produce. Now, an MIT team has found a way to produce more complicated structures by using a blend of current "top-down" and "bottom-up" approaches.

A new way to build nanostructures: Combining top-down and bottom-up approaches, new low-cost method could be a boon to research with a variety of applications.

Cambridge, MA | Posted on July 6th, 2011

The work is described in a paper published in June in the journal Nano Letters, co-authored by postdoc Chih-Hao Chang; George Barbastathis, the Singapore Research Professor of Optics and Professor of Mechanical Engineering; and six MIT graduate students.

One approach to making three-dimensional nanostructures — a top-down approach — is called phase-shift lithography, in which a two-dimensional mask shapes the intensity of light shining onto a layer of photoresist material (in the same way a photographic negative controls the amount of light reaching different areas of a print). The photoresist is altered only in the areas reached by the light. However, this approach requires very precisely manufactured phase masks, which are expensive and time-consuming to make.

Another method — a bottom-up approach — is to use self-assembling colloidal nanoparticles that form themselves into certain energetically favorable close-packed arrangements. These can then be used as a mask for physical deposition methods, such as vapor deposition, or etching of the surface, to produce 2-D structures, just as a stencil can be used to control where paint reaches a surface. But these methods are slow and limited by defects that can form in the self-assembly process, so although they can be used for the fabrication of 3-D structures, this is made difficult because any defects propagate through the layers.

"We do a little bit of both," Chang says. "We took a chemist's method and added in a flavor of engineering."

The new method is a hybrid in which the self-assembled array is produced directly on a substrate material, performing the function of a mask for the lithography process. The individual nanoparticles that assemble on the surface each act as tiny lenses, focusing the beam into an intensity pattern determined by their arrangement on the surface. The method, the authors say in their paper, "can be implemented as a novel technique to fabricate complex 3-D nanostructures in all fields of nanoscale research."

Depending on the shapes and arrangements of the tiny glass beads they use for the self-assembly part of the process, it is possible to create a great variety of structures, "from holes to higher-density posts, rings, flowery structures, all using the exact same system," Chang says. "It's a very simple way to make 3-D nanostructures, and probably the cheapest way right now. You can use it for many things."

Team members, whose specialty is in optics, say the first structures they plan to make are photonic crystals, whose structure can manipulate the behavior of light beams passing through them. But the method can also be used to make phononic materials, which control waves of heat or sound, or even to make filters with precisely controlled porosity, which might have biomedical applications.

John Rogers SM '92, PhD '95, a professor of materials science and engineering and professor of chemistry at the University of Illinois at Urbana-Champaign who was not involved in this work, says these MIT researchers have found "a remarkably simple way to do a very hard thing in nanofabrication, i.e., to create large-scale, three-dimensional nanostructures with useful shapes."

Rogers says, "The experimental simplicity, and the resulting access to structures that would be difficult or impossible to achieve in other ways, suggest that the approach will be useful for many fields of application, ranging from photonic crystals to engineered filter membranes and others."

Written by David Chandler, MIT News Office

####

For more information, please click here

Contacts:
Marta Buczek
MIT News Office

617.253.2702

Copyright © MIT

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 News Press

News and information

Nanodiamonds Are Forever: A UCSB professor’s research examines 13,000-year-old nanodiamonds from multiple locations across three continents August 27th, 2014

Aspen Aerogels, Inc. to Present at Barclays CEO Energy-Power Conference August 27th, 2014

Nanotech Security Corp. to Acquire Fortress Optical Features Ltd., a Leading Producer of Banknote Security Features August 27th, 2014

Malvern specialists to deliver inaugural short course on polymer characterization at Interplas 2014 August 27th, 2014

3D printing

Micro-manufacturing breakthrough is wired for sound June 24th, 2014

3D printing and microrobots making progress on building tissue with blood vessels which will enable large printed organs June 1st, 2014

NTU launches $30 million 3D printing research centre: New centre to establish $5 million joint-lab for 3D printing with industry leader SLM Solutions May 28th, 2014

3-D printing and custom manufacturing: from concept to classroom: Strategic investments from NSF help engineers revolutionize the manufacturing process December 5th, 2013

Chip Technology

Scientists craft atomically seamless, thinnest-possible semiconductor junctions August 26th, 2014

RMIT delivers $30m boost to micro and nano-tech August 26th, 2014

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

Symphony of nanoplasmonic and optical resonators leads to magnificent laser-like light emission August 26th, 2014

Nanomedicine

The thunder god vine, assisted by nanotechnology, could shake up future cancer treatment: Targeted therapy for hepatocellular carcinoma using nanotechnology August 27th, 2014

Introducing the multi-tasking nanoparticle: Versatile particles offer a wide variety of diagnostic and therapeutic applications August 26th, 2014

Symphony of nanoplasmonic and optical resonators leads to magnificent laser-like light emission August 26th, 2014

Silver Replaced with Copper Nanoparticles to Produce Antibacterial Fabrics August 25th, 2014

Nanoelectronics

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

A*STAR and industry form S$200M semiconductor R&D July 25th, 2014

A Crystal Wedding in the Nanocosmos July 23rd, 2014

3-D nanostructure could benefit nanoelectronics, gas storage: Rice U. researchers predict functional advantages of 3-D boron nitride July 15th, 2014

Discoveries

The thunder god vine, assisted by nanotechnology, could shake up future cancer treatment: Targeted therapy for hepatocellular carcinoma using nanotechnology August 27th, 2014

Introducing the multi-tasking nanoparticle: Versatile particles offer a wide variety of diagnostic and therapeutic applications August 26th, 2014

Scientists craft atomically seamless, thinnest-possible semiconductor junctions August 26th, 2014

Creation of a Highly Efficient Technique to Develop Low-Friction Materials Which Are Drawing Attention in Association with Energy Issues August 26th, 2014

Materials/Metamaterials

Nanodiamonds Are Forever: A UCSB professor’s research examines 13,000-year-old nanodiamonds from multiple locations across three continents August 27th, 2014

Creation of a Highly Efficient Technique to Develop Low-Friction Materials Which Are Drawing Attention in Association with Energy Issues August 26th, 2014

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

Thermal Block Coatings Developed in Iran Using Nanotechnology August 26th, 2014

Announcements

Nanodiamonds Are Forever: A UCSB professor’s research examines 13,000-year-old nanodiamonds from multiple locations across three continents August 27th, 2014

Aspen Aerogels, Inc. to Present at Barclays CEO Energy-Power Conference August 27th, 2014

Nanotech Security Corp. to Acquire Fortress Optical Features Ltd., a Leading Producer of Banknote Security Features August 27th, 2014

Malvern specialists to deliver inaugural short course on polymer characterization at Interplas 2014 August 27th, 2014

Photonics/Optics/Lasers

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

Symphony of nanoplasmonic and optical resonators leads to magnificent laser-like light emission August 26th, 2014

Biomimetic photodetector 'sees' in color: Rice lab uses CMOS-compatible aluminum for on-chip color detection August 25th, 2014

Ultra-short pulse lasers & Positioning August 21st, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE