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

Ultracold atom waves may shed light on rogue ocean killers: Rice quantum experiments probe underlying physics of rogue ocean waves April 27th, 2017

Looking for the quantum frontier: Beyond classical computing without fault-tolerance? April 27th, 2017

Metal nanoparticles induced visible-light photocatalysis: Mechanisms, applications, ways of promoting catalytic activity and outlook April 27th, 2017

Arrowhead Pharmaceuticals to Webcast Fiscal 2017 Second Quarter Results April 27th, 2017

Thin films

Nanomechanics, Inc. Unveils New Product at ICMCTF Show April 25th: Nanoindentation experts will launch the new Gemini that measures the interaction of two objects that are sliding across each other – not merely making contact April 21st, 2017

Nanomechanics Inc. President Warren Oliver, PhD to Present at ICMCTF: Nanoindentation experts will discuss new testing system that measures the interaction of two objects that are sliding across each other – not merely making contact April 17th, 2017

Bio-inspired energy storage: A new light for solar power: Graphene-based electrode prototype, inspired by fern leaves, could be the answer to solar energy storage challenge April 2nd, 2017

Display technology/LEDs/SS Lighting/OLEDs

New ultrafast flexible and transparent memory devices could herald new era of electronics April 1st, 2017

UC researchers use gold coating to control luminescence of nanowires: University of Cincinnati physicists manipulate nanowire semiconductors in pursuit of making electronics smaller, faster and cheaper March 17th, 2017

Perovskite edges can be tuned for optoelectronic performance: Layered 2D material improves efficiency for solar cells and LEDs March 10th, 2017

Research opens door to smaller, cheaper, more agile communications tech February 16th, 2017

Govt.-Legislation/Regulation/Funding/Policy

Ultracold atom waves may shed light on rogue ocean killers: Rice quantum experiments probe underlying physics of rogue ocean waves April 27th, 2017

Metal nanoparticles induced visible-light photocatalysis: Mechanisms, applications, ways of promoting catalytic activity and outlook April 27th, 2017

Graphene holds up under high pressure: Used in filtration membranes, ultrathin material could help make desalination more productive April 24th, 2017

Nanoparticle vaccine shows potential as immunotherapy to fight multiple cancer types April 24th, 2017

Chip Technology

Geoffrey Beach: Drawn to explore magnetism: Materials researcher is working on the magnetic memory of the future April 25th, 2017

'Neuron-reading' nanowires could accelerate development of drugs for neurological diseases April 12th, 2017

Nanometrics to Announce First Quarter Financial Results on May 2, 2017 April 11th, 2017

AIM Photonics Presents Cutting-Edge Integrated Photonics Technology Developments to Packed House at OFC 2017, the Optical Networking and Communication Conference & Exhibition April 11th, 2017

Sensors

Better living through pressure: Functional nanomaterials made easy April 19th, 2017

A Sensitive And Dynamic Tactile Sensor Read more from Asian Scientist Magazine at: https://www.asianscientist.com/2017/04/tech/tactile-3d-active-matrix-sensor/ April 18th, 2017

AIM Photonics Presents Cutting-Edge Integrated Photonics Technology Developments to Packed House at OFC 2017, the Optical Networking and Communication Conference & Exhibition April 11th, 2017

New technology could offer cheaper, faster food testing: Specialized droplets interact with bacteria and can be analyzed using a smartphone April 7th, 2017

Discoveries

Ultracold atom waves may shed light on rogue ocean killers: Rice quantum experiments probe underlying physics of rogue ocean waves April 27th, 2017

Looking for the quantum frontier: Beyond classical computing without fault-tolerance? April 27th, 2017

Metal nanoparticles induced visible-light photocatalysis: Mechanisms, applications, ways of promoting catalytic activity and outlook April 27th, 2017

Geoffrey Beach: Drawn to explore magnetism: Materials researcher is working on the magnetic memory of the future April 25th, 2017

Announcements

Ultracold atom waves may shed light on rogue ocean killers: Rice quantum experiments probe underlying physics of rogue ocean waves April 27th, 2017

Looking for the quantum frontier: Beyond classical computing without fault-tolerance? April 27th, 2017

Metal nanoparticles induced visible-light photocatalysis: Mechanisms, applications, ways of promoting catalytic activity and outlook April 27th, 2017

Arrowhead Pharmaceuticals to Webcast Fiscal 2017 Second Quarter Results April 27th, 2017

Military

Ultracold atom waves may shed light on rogue ocean killers: Rice quantum experiments probe underlying physics of rogue ocean waves April 27th, 2017

Nano-SPEARs gently measure electrical signals in small animals: Rice University's tiny needles simplify data gathering to probe diseases, test drugs April 17th, 2017

New technology could offer cheaper, faster food testing: Specialized droplets interact with bacteria and can be analyzed using a smartphone April 7th, 2017

Teri Odom and Richard Van Duyne Honored by Department of Defense: Each will receive $3 million over five years to conduct high-risk, high-payoff research March 31st, 2017

Energy

Using light to propel water : With new method, MIT engineers can control and separate fluids on a surface using only visible light April 25th, 2017

SUNY Polytechnic Institute Announces Total of 172 Teams Selected to Compete in Solar in Your Community Challenge: Teams from 40 states, plus Washington, DC, 2 Territories, and 4 American Indian Reservations, Will Deploy Solar in Underserved Communities April 20th, 2017

Better living through pressure: Functional nanomaterials made easy April 19th, 2017

Shedding light on the absorption of light by titanium dioxide April 14th, 2017

Photonics/Optics/Lasers

Using light to propel water : With new method, MIT engineers can control and separate fluids on a surface using only visible light April 25th, 2017

Method improves semiconductor fiber optics, paves way for developing devices April 16th, 2017

AIM Photonics Presents Cutting-Edge Integrated Photonics Technology Developments to Packed House at OFC 2017, the Optical Networking and Communication Conference & Exhibition April 11th, 2017

Photonics breakthough paving the way for improved wireless communication systems: The work could bolster the wireless revolution underway with efficiencies several orders of magnitude April 5th, 2017

Solar/Photovoltaic

SUNY Polytechnic Institute Announces Total of 172 Teams Selected to Compete in Solar in Your Community Challenge: Teams from 40 states, plus Washington, DC, 2 Territories, and 4 American Indian Reservations, Will Deploy Solar in Underserved Communities April 20th, 2017

Better living through pressure: Functional nanomaterials made easy April 19th, 2017

Shedding light on the absorption of light by titanium dioxide April 14th, 2017

Controlling forces between atoms, molecules, promising for ‘2-D hyperbolic’ materials April 4th, 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