Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Researchers Stitch Defects into the World’s Thinnest Semiconductor

A false-color electron microscopy image showing the star-shaped crystals in monolayers of two-dimensional semiconducting molybdenum disulfide. The red, yellow, and blue colors represent two dominant crystal orientations that are stitched together by a line of atomic defects. Image courtesy of Pinshane Y. Huang and David A. Muller
A false-color electron microscopy image showing the star-shaped crystals in monolayers of two-dimensional semiconducting molybdenum disulfide. The red, yellow, and blue colors represent two dominant crystal orientations that are stitched together by a line of atomic defects.

Image courtesy of Pinshane Y. Huang and David A. Muller

Abstract:
In pioneering new research at Columbia University, scientists have grown high-quality crystals of molybdenum disulfide (MoS2), the world's thinnest semiconductor, and studied how these crystals stitch together at the atomic scale to form continuous sheets. Through beautiful images of strikingly symmetric stars and triangles hundreds of microns across, they have uncovered key insights into the optical and electronic properties of this new material, which can be either conducting or insulating to form the basic "on-off switch" for all digital electronics. The study is published in the May 5, 2013, issue of Nature Materials.

Researchers Stitch Defects into the World’s Thinnest Semiconductor

New York, NY | Posted on May 22nd, 2013

"Our research is the first to systematically examine what kinds of defects result from these large growths, and to investigate how those defects change its properties," says James Hone, professor of mechanical engineering at Columbia Engineering, who led the study. "Our results will help develop ways to use this new material in atomically thin electronics that will become integral components of a whole new generation of revolutionary products such as flexible solar cells that conform to the body of a car."

This multidisciplinary collaboration by the Energy Frontier Research Center at Columbia University with Cornell University's Kavli Institute for Nanoscale Science focused on molybdenum disulfide because of its potential to create anything from highly efficient, flexible solar cells to conformable touch displays. Earlier work from Columbia demonstrated that monolayer MoS2 has an electronic structure distinct from the bulk form, and the researchers are excited about exploring other atomically thin metal dichalcogenides, which should have equally interesting properties. MoS2 is in a class of materials called transition metal dichalcogenides, which can be metals, semiconductors, dielectrics, and even superconductors.

"This material is the newest in a growing family of two-dimensional crystals," says Arend van der Zande, a research fellow at the Columbia Energy Frontier Research Center and one of the paper's three lead authors. "Graphene, a single sheet of carbon atoms, is the thinnest electrical conductor we know. With the addition of the monolayer molybdenum disulfide and other metal dichalcogenides, we have all the building blocks for modern electronics that must be created in atomically thin form. For example, we can now imagine sandwiching two different monolayer transition metal dichalcogenides between layers of graphene to make solar cells that are only eight atoms thick—20 thousand times smaller than a human hair!"

Until last year, the majority of experiments studying MoS2 were done by a process called mechanical exfoliation, which only produces samples just a few micrometers in size. "While these tiny specimens are fine for scientific studies," notes Daniel Chenet, a PhD in Hone's lab and another lead author, "they are much too small for use in any technological application. Figuring out how to grow these materials on a large scale is critical."

To study the material, the researchers refined an existing technique to grow large, symmetric crystals up to 100 microns across, but only three atoms thick. "If we could expand one of these crystals to the thickness of a sheet of plastic wrap, it would be large enough to cover a football field—and it would not have any misaligned atoms," says Pinshane Huang, a PhD student in the David Muller lab at Cornell and the paper's third lead author.

For use in many applications, these crystals need to be joined together into continuous sheets like patches on a quilt. The connections between the crystals, called grain boundaries, can be as important as the crystals themselves in determining the material's performance on a large scale. "The grain boundaries become important in any technology," says Hone. "Say, for example, we want to make a solar cell. Now we need to have meters of this material, not micrometers, and that means that there will be thousands of grain boundaries. We need to understand what they do so we can control them."

The team used atomic-resolution electron microscopy to examine the grain boundaries of this material, and saw lines of misaligned atoms. Once they knew where to find the grain boundaries, and what they looked like, the team could study the effect of a single grain boundary on the properties of the MoS2. To do this, they built tiny transistors, the most basic component in all of electronics, out of the crystals and saw that the single, defective line of atoms at the grain boundaries could drastically change the key electronic and optical properties of the MoS2.

"We've made a lot of progress in controlling the growth of this new ‘wonder' nanomaterial and are now developing techniques to integrate it into many new technologies," Hone adds. "We're only just beginning to scratch the surface of what we can make with these materials and what their properties are. For instance, we can easily remove this material from the growth substrate and transfer it on to any arbitrary surface, which enables us to integrate it into large-scale, flexible electronics and solar cells."

The crystal synthesis, optical measurements, electronic measurements, and theory were all performed by research groups at Columbia Engineering. The growth and electrical measurements were made by the Hone lab in mechanical engineering; the optical measurements were carried out in the Tony Heinz lab in physics. The structural modeling and electronic structure calculations were performed by the David Reichman lab in chemistry. The electron microscopy was performed by atomic imaging experts in the David Muller lab at Cornell University's School of Applied and Engineering Physics, and the Kavli Institute at Cornell for Nanoscale Science.

The study was sponsored by the Columbia Energy Frontier Research Center, with additional support provided by the National Science Foundation through the Cornell Center for Materials Research.

####

For more information, please click here

Contacts:
Holly Evarts
Director
Strategic Communications and Media Relations
347-453-7408 (c)
212-854-3206 (o)

Copyright © Columbia Engineering

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

Raman Whispering Gallery Detects Nanoparticles September 1st, 2014

A new, tunable device for spintronics: An international team of scientists including physicist Jairo Sinova from the University of Mainz realises a tunable spin-charge converter made of GaAs August 29th, 2014

Nanoscale assembly line August 29th, 2014

New Vice President Takes Helm at CNSE CMOST: Catherine Gilbert To Lead CNSE Children’s Museum of Science and Technology Through Expansion And Relocation August 29th, 2014

Flexible Electronics

Copper shines as flexible conductor August 29th, 2014

Nanoengineers Develop Basis for Electronics That Stretch at the Molecular Level May 8th, 2014

Energy device for flexible electronics packs a lot of power May 7th, 2014

Flexible battery, no lithium required: Rice University lab creates thin-film battery for portable, wearable electronics April 28th, 2014

Chip Technology

New analytical technology reveals 'nanomechanical' surface traits August 29th, 2014

Fonon Announces 3D Metal Sintering Technology: Emerging Additive Nano Powder Manufacturing Technology August 28th, 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

Discoveries

Raman Whispering Gallery Detects Nanoparticles September 1st, 2014

A new, tunable device for spintronics: An international team of scientists including physicist Jairo Sinova from the University of Mainz realises a tunable spin-charge converter made of GaAs August 29th, 2014

Nanoscale assembly line August 29th, 2014

Copper shines as flexible conductor August 29th, 2014

Announcements

Raman Whispering Gallery Detects Nanoparticles September 1st, 2014

Nanoscale assembly line August 29th, 2014

New analytical technology reveals 'nanomechanical' surface traits August 29th, 2014

New Vice President Takes Helm at CNSE CMOST: Catherine Gilbert To Lead CNSE Children’s Museum of Science and Technology Through Expansion And Relocation August 29th, 2014

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals

Raman Whispering Gallery Detects Nanoparticles September 1st, 2014

A new, tunable device for spintronics: An international team of scientists including physicist Jairo Sinova from the University of Mainz realises a tunable spin-charge converter made of GaAs August 29th, 2014

Nanoscale assembly line August 29th, 2014

New analytical technology reveals 'nanomechanical' surface traits August 29th, 2014

Tools

Raman Whispering Gallery Detects Nanoparticles September 1st, 2014

New analytical technology reveals 'nanomechanical' surface traits August 29th, 2014

Ultra-Low Frequency Vibration Isolation Stabilizes Scanning Tunneling Microscopy at UCLA’s Nano-Research Group August 28th, 2014

Measure Both Elastic and Viscous Properties with AFM Using Asylum Research’s Exclusive AM-FM Viscoelastic Mapping Mode August 28th, 2014

Energy

Novel 'butterfly' molecule could build new sensors, photoenergy conversion devices August 28th, 2014

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

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

Chemical reaction yields "tapes" of porphin molecules: Flexible tapes from the nanoworld August 13th, 2014

Automotive/Transportation

Fonon Announces 3D Metal Sintering Technology: Emerging Additive Nano Powder Manufacturing Technology August 28th, 2014

SouthWest NanoTechnologies CEO Dave Arthur to Discuss “Carbon Nanotubes and Automotive Applications” at The Automotive Composites Conference and Expo 2014 (ACCE2014) August 28th, 2014

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

New Method Provides Nanoscale Details of Electrochemical Reactions in Electric Vehicle Battery Materials August 4th, 2014

Research partnerships

Leading European communications companies and research organizations have launched an EU project developing the future 5th Generation cellular mobile networks August 28th, 2014

New technique uses fraction of measurements to efficiently find quantum wave functions August 28th, 2014

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

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

Solar/Photovoltaic

Novel 'butterfly' molecule could build new sensors, photoenergy conversion devices August 28th, 2014

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

Eco-friendly 'pre-fab nanoparticles' could revolutionize nano manufacturing: UMass Amherst team invents a way to create versatile, water-soluble nano-modules August 13th, 2014

An Inkjet-Printed Field-Effect Transistor for Label-Free Biosensing August 11th, 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