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

Two Scientists Receive Grants to Develop New Materials: Chad Mirkin and Monica Olvera de la Cruz recognized by Sherman Fairchild Foundation August 16th, 2017

Fewer defects from a 2-D approach August 15th, 2017

Scientists from the University of Manchester and Diamond Light Source work with Deben to develop and test a new compression stage to study irradiated graphite at elevated temperatures August 15th, 2017

Oxford Instruments Plasma Technology announces a new partner in Korea August 15th, 2017

Display technology/LEDs/SS Lighting/OLEDs

Nanocrystalline LEDs: Red, green, yellow, blue ... August 7th, 2017

Nanoparticles could spur better LEDs, invisibility cloaks July 19th, 2017

Thin films

Rice University chemists make laser-induced graphene from wood July 31st, 2017

Graduate Students from Across the Country Attend Hands-on NanoCamp: Prominent scientists Warren Oliver, Ph.D., and George Pharr, Ph.D., presented a weeklong NanoCamp for hand-picked graduate students across the United States July 26th, 2017

Studying Argon Gas Trapped in Two-Dimensional Array of Tiny "Cages": Understanding how individual atoms enter and exit the nanoporous frameworks could help scientists design new materials for gas separation and nuclear waste remediation July 17th, 2017

Govt.-Legislation/Regulation/Funding/Policy

2-faced 2-D material is a first at Rice: Rice University materials scientists create flat sandwich of sulfur, molybdenum and selenium August 14th, 2017

Engineers pioneer platinum shell formation process – and achieve first-ever observation August 11th, 2017

Moving at the Speed of Light: University of Arizona selected for high-impact, industrial demonstration of new integrated photonic cryogenic datalink for focal plane arrays: Program is major milestone for AIM Photonics August 10th, 2017

Sensing technology takes a quantum leap with RIT photonics research: Office of Naval Research funds levitated optomechanics project August 10th, 2017

Chip Technology

Two Scientists Receive Grants to Develop New Materials: Chad Mirkin and Monica Olvera de la Cruz recognized by Sherman Fairchild Foundation August 16th, 2017

Surprise discovery in the search for energy efficient information storage August 10th, 2017

GLOBALFOUNDRIES Demonstrates 2.5D High-Bandwidth Memory Solution for Data Center, Networking, and Cloud Applications: Solution leverages 2.5D packaging with low-latency, high-bandwidth memory PHY built on FX-14™ ASIC design system August 9th, 2017

Nanometrics Announces Upcoming Investor Events August 3rd, 2017

Sensors

Sensing technology takes a quantum leap with RIT photonics research: Office of Naval Research funds levitated optomechanics project August 10th, 2017

Giant enhancement of electromagnetic waves revealed within small dielectric particles: Scientists have done for the first time direct measurements of giant electromagnetic fields July 8th, 2017

Bosch announces high-performance MEMS acceleration sensors for wearables June 27th, 2017

Leti’s Autonomous-Vehicle System Embedded in Infineon’s AURIX Platform: Leti’s Low-Power, Multi-Sensor System that Transforms Distance Data into Clear Information About the Driving Environment Will Be Demonstrated at ITS Meeting in Strasbourg, June 19-22 June 20th, 2017

Discoveries

Fewer defects from a 2-D approach August 15th, 2017

Scientists from the University of Manchester and Diamond Light Source work with Deben to develop and test a new compression stage to study irradiated graphite at elevated temperatures August 15th, 2017

2-faced 2-D material is a first at Rice: Rice University materials scientists create flat sandwich of sulfur, molybdenum and selenium August 14th, 2017

Engineers pioneer platinum shell formation process – and achieve first-ever observation August 11th, 2017

Announcements

Two Scientists Receive Grants to Develop New Materials: Chad Mirkin and Monica Olvera de la Cruz recognized by Sherman Fairchild Foundation August 16th, 2017

Fewer defects from a 2-D approach August 15th, 2017

Scientists from the University of Manchester and Diamond Light Source work with Deben to develop and test a new compression stage to study irradiated graphite at elevated temperatures August 15th, 2017

Oxford Instruments Plasma Technology announces a new partner in Korea August 15th, 2017

Military

2-faced 2-D material is a first at Rice: Rice University materials scientists create flat sandwich of sulfur, molybdenum and selenium August 14th, 2017

Moving at the Speed of Light: University of Arizona selected for high-impact, industrial demonstration of new integrated photonic cryogenic datalink for focal plane arrays: Program is major milestone for AIM Photonics August 10th, 2017

Sensing technology takes a quantum leap with RIT photonics research: Office of Naval Research funds levitated optomechanics project August 10th, 2017

Landscapes give latitude to 2-D material designers: Rice University, Oak Ridge scientists show growing atom-thin sheets on cones allows control of defects August 9th, 2017

Energy

Two Scientists Receive Grants to Develop New Materials: Chad Mirkin and Monica Olvera de la Cruz recognized by Sherman Fairchild Foundation August 16th, 2017

Fewer defects from a 2-D approach August 15th, 2017

2-faced 2-D material is a first at Rice: Rice University materials scientists create flat sandwich of sulfur, molybdenum and selenium August 14th, 2017

Controlled manipulation: Scientists at FAU are investigating the properties of hybrid systems consisting of carbon nanostructures and a dye August 8th, 2017

Photonics/Optics/Lasers

Moving at the Speed of Light: University of Arizona selected for high-impact, industrial demonstration of new integrated photonic cryogenic datalink for focal plane arrays: Program is major milestone for AIM Photonics August 10th, 2017

Sensing technology takes a quantum leap with RIT photonics research: Office of Naval Research funds levitated optomechanics project August 10th, 2017

High resolution without particle accelerator: A first for physics -- University of Jena physicists are first to achieve optical coherence tomography with XUV radiation at laboratory scale August 7th, 2017

Simultaneous Design and Nanomanufacturing Speeds Up Fabrication: Method enhances broadband light absorption in solar cells August 5th, 2017

Solar/Photovoltaic

Fewer defects from a 2-D approach August 15th, 2017

Controlled manipulation: Scientists at FAU are investigating the properties of hybrid systems consisting of carbon nanostructures and a dye August 8th, 2017

Simultaneous Design and Nanomanufacturing Speeds Up Fabrication: Method enhances broadband light absorption in solar cells August 5th, 2017

Atomic movies may help explain why perovskite solar cells are more efficient: SLAC's ultrafast 'electron camera' captures surprising atomic motions in these next-generation materials July 28th, 2017

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