Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Scalable CVD process for making 2-D molybdenum diselenide: Rice, NTU scientists unveil CVD production for coveted 2-D semiconductor

This image from a scanning transmission electron microscope shows the individual atoms in a two-dimensional sheet of molybdenum diselenide.
CREDIT: E. Ringe/Rice University
This image from a scanning transmission electron microscope shows the individual atoms in a two-dimensional sheet of molybdenum diselenide.

CREDIT: E. Ringe/Rice University

Abstract:
Nanoengineering researchers at Rice University and Nanyang Technological University in Singapore have unveiled a potentially scalable method for making one-atom-thick layers of molybdenum diselenide -- a highly sought semiconductor that is similar to graphene but has better properties for making certain electronic devices like switchable transistors and light-emitting diodes.

Scalable CVD process for making 2-D molybdenum diselenide: Rice, NTU scientists unveil CVD production for coveted 2-D semiconductor

Houston, TX | Posted on April 8th, 2014

The method for making two-dimensional molybdenum diselenide uses a technique known as chemical vapor deposition (CVD) and is described online in a new paper in the American Chemical Society journal ACS Nano. The finding is significant because CVD is widely used by the semiconductor and materials industries to make thin films of silicon, carbon fibers and other materials.

"This new method will allow us to exploit the properties of molybdenum diselenide in a number of applications," said study leader Pulickel Ajayan, chair of Rice's Department of Materials Science and NanoEngineering. "Unlike graphene, which can now easily be made in large sheets, many interesting 2-D materials remain difficult to synthesize. Now that we have a stable, efficient way to produce 2-D molybdenum diselenide, we are planning to expand this robust procedure to other 2-D materials."

In the Rice study, Ajayan and colleagues tested their atomically thin layers of molybdenum diselenide by building a field effect transistor (FET), a commonly used device in the microelectronic industry. Tests of the FET found the electronic properties of the molybdenum diselenide layers were significantly better than those of molybdenum disulfide; the latter is a similar material that has been more extensively studied because it was easier to fabricate. For example, the FET tests found that the electron mobility of Rice's molybdenum diselenide was higher than that of CVD-grown, molybdenum disulfide.

In solid-state physics, electron mobility refers to how quickly electrons pass through a metal or semiconductor in the presence of an electric field. Materials with high electron mobility are often preferred to reduce power consumption and heating in microelectronic devices.

"Being able to make 2-D materials in a controlled fashion really will make an impact on our understanding and use of their fascinating properties," said study co-author Emilie Ringe, assistant professor of materials science and nanoengineering and of chemistry at Rice. "Characterizing both the structure and function of a material, as we have done in this paper, is critical to such advances."

Molybdenum diselenide and molybdenum disulfide each belong to a class of materials known as transition metal dichalcogenides; TMDCs are so named because they consist of two elements, a transition metal like molybdenum or tungsten and a "chalcogen" like sulfur, selenium or tellurium.

TMDCs have attracted intense interest from materials scientists because they have an atomic structure similar to graphene, the pure carbon wonder materials that attracted the 2010 Nobel Prize in physics. Graphene and similar materials are often referred to as two-dimensional because they are only one atom thick. Graphene has extraordinary electronic properties. For example, its electron mobility is tens of thousands of times greater than that of TMDCs.

However, two-dimensional TMDCs like molybdenum diselenide have attracted intense interest because their electronic properties are complementary to graphene. For example, pure graphene has no bandgap -- a useful electronic property that engineers can exploit to make FETs that are easily switched on and off.

As with many nanomaterials, scientists have found that the physical properties of TMDCs change markedly when the material has nanoscale properties. For example, a slab of molybdenum diselenide that is even a micron thick has an "indirect" bandgap while a two-dimensional sheet of molybdenum diselenide has a "direct" bandgap. The difference is important for electronics because direct-bandgap materials can be used to make switchable transistors and sensitive photodetectors.

"One of the driving forces in Rice's Department of Materials Science and NanoEngineering is the close collaborations that develop between the people who are focused on synthesis and those of us involved with characterization," said Ringe, who joined Rice's faculty in January. "We hope this will be the beginning of a series of new protocols to reliably synthesize a variety of 2-D materials."

The research was supported by the Army Research Office, the Semiconductor Research Corporation's FAME Center, the Office of Naval Research and Singapore's MOE Academic Research Fund.

Additional study co-authors include Xingli Wang, Yongji Gong, Gang Shi, Kunttal Keyshar, Gonglan Ye, Robert Vajtai and Jun Lou, all of Rice, and Wai Leong Chow, Zheng Liu and Beng Kang Tay, all of Nanyang Technological University.

####

About Rice University
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,920 undergraduates and 2,567 graduate students, Rice's undergraduate student-to-faculty ratio is 6.3-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice has been ranked No. 1 for best quality of life multiple times by the Princeton Review and No. 2 for "best value" among private universities by Kiplinger's Personal Finance.

For more information, please click here

Contacts:
Jade Boyd
713-348-6778

Copyright © Rice University

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 Links

A copy of the ACS Nano paper is available at:

More information about Rice's Department of Materials Science and NanoEngineering:

Related News Press

Graphene

Light pulses control graphene's electrical behavior: Finding could allow ultrafast switching of conduction, and possibly lead to new broadband light sensors August 1st, 2014

Pressure probing potential photoelectronic manufacturing compound July 31st, 2014

FLAG-ERA and TNT2014 join efforts: Graphene Networking at its higher level in Barcelona: Encourage the participation in a joint transnational call July 30th, 2014

Tough foam from tiny sheets: Rice University lab uses atom-thick materials to make ultralight foam July 29th, 2014

News and information

Light pulses control graphene's electrical behavior: Finding could allow ultrafast switching of conduction, and possibly lead to new broadband light sensors August 1st, 2014

President Obama Meets U.S. Laureates of 2014 Kavli Prizes August 1st, 2014

Stanford researchers seek 'Holy Grail' in battery design: Pure lithium anode closer to reality with development of protective layer of interconnected carbon domes August 1st, 2014

Air Force’s 30-year plan seeks 'strategic agility' August 1st, 2014

Thin films

Nanostructured metal-oxide catalyst efficiently converts CO2 to methanol: Highly reactive sites at interface of 2 nanoscale components could help overcome hurdle of using CO2 as a starting point in producing useful products July 31st, 2014

Even geckos can lose their grip July 9th, 2014

Display technology/LEDs/SS Lighting/OLEDs

Martini Tech Inc. becomes the exclusive distributor for Yoshioka Seiko Co. porous chucks for Europe and North America July 20th, 2014

Carbodeon enables 20 percent increase in polymer thermal filler conductivity with 0.03 wt.% nanodiamond additive at a lower cost than with traditional fillers: Improved materials and processes enable nanodiamond cost reductions of up to 70 percent for electronics and LED app July 9th, 2014

'Nano-pixels' promise thin, flexible, high resolution displays July 9th, 2014

Govt.-Legislation/Regulation/Funding/Policy

Light pulses control graphene's electrical behavior: Finding could allow ultrafast switching of conduction, and possibly lead to new broadband light sensors August 1st, 2014

President Obama Meets U.S. Laureates of 2014 Kavli Prizes August 1st, 2014

Stanford researchers seek 'Holy Grail' in battery design: Pure lithium anode closer to reality with development of protective layer of interconnected carbon domes August 1st, 2014

Air Force’s 30-year plan seeks 'strategic agility' August 1st, 2014

Chip Technology

Pressure probing potential photoelectronic manufacturing compound July 31st, 2014

Nanometrics Reports Second Quarter 2014 Financial Results July 30th, 2014

A*STAR and industry form S$200M semiconductor R&D July 25th, 2014

A Crystal Wedding in the Nanocosmos July 23rd, 2014

Discoveries

Iranian Scientists Produce Cobalt–Alumina Ceramic Nano Inks August 1st, 2014

Light pulses control graphene's electrical behavior: Finding could allow ultrafast switching of conduction, and possibly lead to new broadband light sensors August 1st, 2014

Taking the guesswork out of cancer therapy: New molecular test kit predicts patient’s survival and drug response August 1st, 2014

Carnegie Mellon Chemists Create Nanofibers Using Unprecedented New Method July 31st, 2014

Announcements

Light pulses control graphene's electrical behavior: Finding could allow ultrafast switching of conduction, and possibly lead to new broadband light sensors August 1st, 2014

President Obama Meets U.S. Laureates of 2014 Kavli Prizes August 1st, 2014

Stanford researchers seek 'Holy Grail' in battery design: Pure lithium anode closer to reality with development of protective layer of interconnected carbon domes August 1st, 2014

Air Force’s 30-year plan seeks 'strategic agility' August 1st, 2014

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

Iranian Scientists Produce Cobalt–Alumina Ceramic Nano Inks August 1st, 2014

Light pulses control graphene's electrical behavior: Finding could allow ultrafast switching of conduction, and possibly lead to new broadband light sensors August 1st, 2014

Stanford researchers seek 'Holy Grail' in battery design: Pure lithium anode closer to reality with development of protective layer of interconnected carbon domes August 1st, 2014

Taking the guesswork out of cancer therapy: New molecular test kit predicts patient’s survival and drug response August 1st, 2014

Military

Air Force’s 30-year plan seeks 'strategic agility' August 1st, 2014

Pressure probing potential photoelectronic manufacturing compound July 31st, 2014

New imaging agent provides better picture of the gut July 30th, 2014

Watching Schrödinger's cat die (or come to life): Steering quantum evolution & using probes to conduct continuous error correction in quantum computers July 30th, 2014

Research partnerships

Study finds physical link to strange electronic behavior: Neutron measurements offer new clues about iron-based superconductor July 31st, 2014

Carnegie Mellon Chemists Create Nanofibers Using Unprecedented New Method July 31st, 2014

New imaging agent provides better picture of the gut July 30th, 2014

Breakthrough laser experiment reveals liquid-like motion of atoms in an ultra-cold cluster: University of Leicester research team unlocks insights into creation of new nano-materials July 25th, 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