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

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Design of micro and nanoparticles to improve treatments for Alzheimers and Parkinsons: At the Faculty of Pharmacy of the UPV/EHU-University of the Basque Country encapsulation techniques are being developed to deliver correctly and effectively certain drugs October 20th, 2014

Physicists build reversible laser tractor beam October 20th, 2014

Removal of Limitations of Composites at Superheat Temperatures October 20th, 2014

3D printing

3DXNano™ ESD Carbon Nanotube 3D Printing Filament - optimized for demanding 3D printing applications in the semi-con and electronics industry October 16th, 2014

ORNL research reveals unique capabilities of 3-D printing October 15th, 2014

Fast, cheap nanomanufacturing: Arrays of tiny conical tips that eject ionized materials could fabricate nanoscale devices cheaply October 4th, 2014

Fonon at Cutting-Edge of 3D Military Printing: Live-Combat Scenarios Could See a Decisive Advantage with 3D Printing September 15th, 2014

Chip Technology

Crystallizing the DNA nanotechnology dream: Scientists have designed the first large DNA crystals with precisely prescribed depths and complex 3D features, which could create revolutionary nanodevices October 20th, 2014

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Superconducting circuits, simplified: New circuit design could unlock the power of experimental superconducting computer chips October 18th, 2014

3DXNano™ ESD Carbon Nanotube 3D Printing Filament - optimized for demanding 3D printing applications in the semi-con and electronics industry October 16th, 2014

Nanomedicine

Design of micro and nanoparticles to improve treatments for Alzheimers and Parkinsons: At the Faculty of Pharmacy of the UPV/EHU-University of the Basque Country encapsulation techniques are being developed to deliver correctly and effectively certain drugs October 20th, 2014

Non-Toxic Nanocatalysts Open New Window for Significant Decrease in Reaction Process October 19th, 2014

European Commission opens the gate towards the implementation of Nanomedicine Translation Hub October 16th, 2014

Tuning light to kill deep cancer tumors: Nanoparticles developed at UMass Medical School advance potential clinical application for photodynamic therapy October 15th, 2014

Nanoelectronics

Crystallizing the DNA nanotechnology dream: Scientists have designed the first large DNA crystals with precisely prescribed depths and complex 3D features, which could create revolutionary nanodevices October 20th, 2014

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Future computers could be built from magnetic 'tornadoes' October 14th, 2014

Aledia’s Nanowire LED Technology Endorsed By 2014 Physics Nobel Prize Winner: Hiroshi Amano Serves on Company’s Scientific Advisory Board October 13th, 2014

Discoveries

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Design of micro and nanoparticles to improve treatments for Alzheimers and Parkinsons: At the Faculty of Pharmacy of the UPV/EHU-University of the Basque Country encapsulation techniques are being developed to deliver correctly and effectively certain drugs October 20th, 2014

Physicists build reversible laser tractor beam October 20th, 2014

Removal of Limitations of Composites at Superheat Temperatures October 20th, 2014

Materials/Metamaterials

Removal of Limitations of Composites at Superheat Temperatures October 20th, 2014

Nanotechnology Improves Quality of Anti-Corrosive Coatings October 17th, 2014

Graphenea opens US branch October 16th, 2014

3DXNano™ ESD Carbon Nanotube 3D Printing Filament - optimized for demanding 3D printing applications in the semi-con and electronics industry October 16th, 2014

Announcements

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Design of micro and nanoparticles to improve treatments for Alzheimers and Parkinsons: At the Faculty of Pharmacy of the UPV/EHU-University of the Basque Country encapsulation techniques are being developed to deliver correctly and effectively certain drugs October 20th, 2014

Physicists build reversible laser tractor beam October 20th, 2014

Removal of Limitations of Composites at Superheat Temperatures October 20th, 2014

Photonics/Optics/Lasers

Physicists build reversible laser tractor beam October 20th, 2014

Magnetic mirrors enable new technologies by reflecting light in uncanny ways October 16th, 2014

New VDMA Association "Electronics, Micro and Nano Technologies" founded: Inaugural Meeting in Frankfurt/Main, Germany October 15th, 2014

Nanodevices for clinical diagnostic with potential for the international market: The development is based on optical principles and provides precision and allows saving vital time for the patient October 15th, 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