Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Patterning defect-free nanocrystal films with nanometer resolution: New process developed at MIT could enable better LED displays, solar cells and biosensors and foster basic physics research

 Images of nanopatterned films of nano crystalline material produced by the MIT research team. Each row shows a different pattern produced on films of either cadmium selenide (top and bottom) or a combination of zinc cadmium selenide and zinc cadmium sulfur (middle row). The three images in each row are made using different kinds of microscopes: left to right, scanning electron microscope, optical (showing real-color fluorescence), and atomic force microscope.
Images courtesy of Mentzel et al, from Nano Letters
Images of nanopatterned films of nano crystalline material produced by the MIT research team. Each row shows a different pattern produced on films of either cadmium selenide (top and bottom) or a combination of zinc cadmium selenide and zinc cadmium sulfur (middle row). The three images in each row are made using different kinds of microscopes: left to right, scanning electron microscope, optical (showing real-color fluorescence), and atomic force microscope.

Images courtesy of Mentzel et al, from Nano Letters

Abstract:
Films made of semiconductor nanocrystals tiny crystals measuring just a few billionths of a meter across are seen as a promising new material for a wide range of applications. Nanocrystals could be used in electronic or photonic circuits, detectors for biomolecules, or the glowing pixels on high-resolution display screens. They also hold promise for more efficient solar cells.

Patterning defect-free nanocrystal films with nanometer resolution: New process developed at MIT could enable better LED displays, solar cells and biosensors and foster basic physics research

Cambridge, MA | Posted on August 20th, 2012

The size of a semiconductor nanocrystal determines its electrical and optical properties. But it's very hard to control the placement of nanocrystals on a surface in order to make structurally uniform films. Typical nanocrystal films also have cracks that limit their usefulness and make it impossible to measure the fundamental properties of these materials.

Now, researchers at MIT say they have found ways of making defect-free patterns of nanocrystal films where the shape and position of the films are controlled with nanoscale resolution, potentially opening up a significant area for research and possible new applications.

"We've been trying to understand how electrons move in arrays of these nanocrystals," which has been difficult with limited control over the formation of the arrays, says physicist Marc Kastner, the Donner Professor of Science, dean of MIT's School of Science and senior author of a paper published online in the journal Nano Letters.

The work builds on research by Moungi Bawendi, the Lester Wolfe Professor of Chemistry at MIT and a co-author of this paper, who was one of the first researchers to precisely control nanocrystal production. Such control made it possible, among other things, to produce materials that glow, or fluoresce, in a range of different colors based on their sizes even though they are all made of the same material.

In the initial phases of the new work, postdoc Tamar Mentzel produced nanoscale patterns that emit invisible infrared light. But working on such systems is tedious, since each fine-tuning has to be checked using time-consuming electron microscopy. So when Mentzel succeeded in getting semiconductor nanocrystal patterns to glow with visible light, making them visible through an optical microscope, it meant that the team could greatly speed the development of the new technology. "Even though the nanoscale patterns are below the resolution limit of the optical microscope, the nanocrystals act as a light source, rendering them visible," Mentzel says.

The electrical conductivity of the researchers' defect-free films is roughly 180 times greater than that of the cracked films made by conventional methods. In addition, the process developed by the MIT team has already made it possible to create patterns on a silicon surface that are just 30 nanometers across about the size of the finest features possible with present manufacturing techniques.

The process is unique in producing such tiny patterns of defect-free films, Mentzel says. "The trick was to get the film to be uniform, and to stick" to the silicon dioxide substrate, Kastner adds. That was achieved by leaving a thin layer of polymer to coat the surface before depositing the layer of nanocrystals on top of it. The researchers conjecture that tiny organic molecules on the surface of the nanocrystals help them bind to the polymer layer.

Such nanocrystal patterns could have many applications, Kastner says. Because these nanocrystals can be tuned not only to emit but also to absorb a wide spectrum of colors of light, they could enable a new kind of broad-spectrum solar cell, he says.

But Kastner and Mentzel's personal interest has more to do with basic physics: Since the minuscule crystals behave almost like oversized atoms, the researchers aim to use the arrays to study fundamental processes of solids, Mentzel says. The success of this technique has already enabled new research on how electrons move in the films.

Such materials could also be used to develop sensitive detectors for tiny amounts of certain biological molecules, either as screening systems for toxins or as medical testing devices, the researchers say.

Douglas Natelson, a professor of physics and astronomy at Rice University who was not involved in this work, says, "The challenge in the past has been achieving thin, uniform films, patterned at high resolution, with good contact between the nanocrystals and no cracking." The MIT team's approach, he says, "while deceptively simple in appearance, accomplishes all of these objectives."

Natelson adds: "I think this is a very nice achievement. The fluorescence images showing the nanopatterned films are eye-popping, particularly for those who know how tough this is."

The research was supported by the U.S Army Research Office, the Department of Energy and Samsung.

Written by: David L. Chandler, MIT News Office

####

For more information, please click here

Contacts:
Caroline McCall
MIT News Office

617-253-1682

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

Picosun patents ALD nanolaminate to prevent electronics from overheating September 28th, 2016

Leti and Taiwanese Tech Organizations Sponsoring Workshop in Taipei on MEMS, IoT, Smart Lighting Applications, System Reliability & Security September 28th, 2016

Fighting cancer with sticky nanoparticles September 27th, 2016

Gold nanoparticles conjugated quercetin inhibits epithelial-mesenchymal transition, angiogenesis and invasiveness via EGFR/VEGFR-2 mediated pathway in breast cancer September 27th, 2016

Display technology/LEDs/SS Lighting/OLEDs

Leti and Taiwanese Tech Organizations Sponsoring Workshop in Taipei on MEMS, IoT, Smart Lighting Applications, System Reliability & Security September 28th, 2016

Thin films

Continuous roll-process technology for transferring and packaging flexible LSI August 29th, 2016

Self-cleaning, anti-reflective, microorganism-resistant coatings: Researchers at the UPV/EHU-University of the Basque Country are modifying surface properties of materials to obtain specific properties at a lower cost August 9th, 2016

Scientists find a way of acquiring graphene-like films from salts to boost nanoelectronics: Physicists use supercomputers to find a way of making 'imitation graphene' from salt July 30th, 2016

Cambridge Advanced Imaging Centre praises support film consistency and quality from EM Resolutions July 5th, 2016

Govt.-Legislation/Regulation/Funding/Policy

Crystalline Fault Lines Provide Pathway for Solar Cell Current: New tomographic AFM imaging technique reveals that microstructural defects, generally thought to be detrimental, actually improve conductivity in cadmium telluride solar cells September 26th, 2016

Tattoo therapy could ease chronic disease: Rice-made nanoparticles tested at Baylor College of Medicine may help control autoimmune diseases September 23rd, 2016

PHENOMEN is a FET-Open Research Project aiming to lay the foundations a new information technology September 19th, 2016

NIST Patents Single-Photon Detector for Potential Encryption and Sensing Apps September 16th, 2016

Chip Technology

Picosun patents ALD nanolaminate to prevent electronics from overheating September 28th, 2016

Researchers at the Catalan Institute of Nanoscience and Nanotechnology show that bending semiconductors generates electricity September 26th, 2016

Mexican scientist in the Netherlands seeks to achieve data transmission ... speed of light September 20th, 2016

Towards Stable Propagation of Light in Nano-Photonic Fibers September 20th, 2016

Sensors

Leti and Taiwanese Tech Organizations Sponsoring Workshop in Taipei on MEMS, IoT, Smart Lighting Applications, System Reliability & Security September 28th, 2016

Researchers at the Catalan Institute of Nanoscience and Nanotechnology show that bending semiconductors generates electricity September 26th, 2016

Chains of nanogold forged with atomic precision September 23rd, 2016

Speedy bacteria detector could help prevent foodborne illnesses September 21st, 2016

Discoveries

Fighting cancer with sticky nanoparticles September 27th, 2016

Gold nanoparticles conjugated quercetin inhibits epithelial-mesenchymal transition, angiogenesis and invasiveness via EGFR/VEGFR-2 mediated pathway in breast cancer September 27th, 2016

UNAM develops successful nano edible coating which increases life food September 27th, 2016

Crystalline Fault Lines Provide Pathway for Solar Cell Current: New tomographic AFM imaging technique reveals that microstructural defects, generally thought to be detrimental, actually improve conductivity in cadmium telluride solar cells September 26th, 2016

Announcements

Picosun patents ALD nanolaminate to prevent electronics from overheating September 28th, 2016

Leti and Taiwanese Tech Organizations Sponsoring Workshop in Taipei on MEMS, IoT, Smart Lighting Applications, System Reliability & Security September 28th, 2016

Fighting cancer with sticky nanoparticles September 27th, 2016

Gold nanoparticles conjugated quercetin inhibits epithelial-mesenchymal transition, angiogenesis and invasiveness via EGFR/VEGFR-2 mediated pathway in breast cancer September 27th, 2016

Military

Tattoo therapy could ease chronic disease: Rice-made nanoparticles tested at Baylor College of Medicine may help control autoimmune diseases September 23rd, 2016

Nano-lipid particles from edible ginger could improve drug delivery for colon cancer, study finds September 8th, 2016

3-D graphene has promise for bio applications: Rice University-led team welds nanoscale sheets to form tough, porous material September 7th, 2016

Nanodiamonds in an instant: Rice University-led team morphs nanotubes into tougher carbon for spacecraft, satellites September 6th, 2016

Energy

Crystalline Fault Lines Provide Pathway for Solar Cell Current: New tomographic AFM imaging technique reveals that microstructural defects, generally thought to be detrimental, actually improve conductivity in cadmium telluride solar cells September 26th, 2016

Researchers at the Catalan Institute of Nanoscience and Nanotechnology show that bending semiconductors generates electricity September 26th, 2016

Semiconducting inorganic double helix: New flexible semiconductor for electronics, solar technology and photo catalysis September 15th, 2016

New perovskite research discoveries may lead to solar cell, LED advances September 12th, 2016

Photonics/Optics/Lasers

Mexican scientist in the Netherlands seeks to achieve data transmission ... speed of light September 20th, 2016

Towards Stable Propagation of Light in Nano-Photonic Fibers September 20th, 2016

PHENOMEN is a FET-Open Research Project aiming to lay the foundations a new information technology September 19th, 2016

NIST Patents Single-Photon Detector for Potential Encryption and Sensing Apps September 16th, 2016

Solar/Photovoltaic

Crystalline Fault Lines Provide Pathway for Solar Cell Current: New tomographic AFM imaging technique reveals that microstructural defects, generally thought to be detrimental, actually improve conductivity in cadmium telluride solar cells September 26th, 2016

Semiconducting inorganic double helix: New flexible semiconductor for electronics, solar technology and photo catalysis September 15th, 2016

New perovskite research discoveries may lead to solar cell, LED advances September 12th, 2016

NREL discovery creates future opportunity in quantum computing: Research into perovskites looks beyond material's usage for efficient solar cells September 9th, 2016

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







Car Brands
Buy website traffic