Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Water Could Hold Answer to Graphene Nanoelectronics

Researchers at Rensselaer Polytechnic Institute developed a new method for using water to tune the band gap of the nanomaterial graphene, opening the door to new graphene-based transistors and nanoelectronics. In this optical micrograph image, a graphene film on a silicon dioxide substrate is being electrically tested using a four-point probe.
Researchers at Rensselaer Polytechnic Institute developed a new method for using water to tune the band gap of the nanomaterial graphene, opening the door to new graphene-based transistors and nanoelectronics. In this optical micrograph image, a graphene film on a silicon dioxide substrate is being electrically tested using a four-point probe.

Abstract:
Researchers at Rensselaer Polytechnic Institute Use Water to Open, Tune Graphene's Band Gap

Water Could Hold Answer to Graphene Nanoelectronics

Troy, NY | Posted on October 26th, 2010

Researchers at Rensselaer Polytechnic Institute developed a new method for using water to tune the band gap of the nanomaterial graphene, opening the door to new graphene-based transistors and nanoelectronics.

By exposing a graphene film to humidity, Rensselaer Professor Nikhil Koratkar and his research team were able to create a band gap in graphene a critical prerequisite to creating graphene transistors. At the heart of modern electronics, transistors are devices that can be switched "on" or "off" to alter an electrical signal. Computer microprocessors are comprised of millions of transistors made from the semiconducting material silicon, for which the industry is actively seeking a successor.

Graphene, an atom-thick sheet of carbon atoms arranged like a nanoscale chain-link fence, has no band gap. Koratkar's team demonstrated how to open a band gap in graphene based on the amount of water they adsorbed to one side of the material, precisely tuning the band gap to any value from 0 to 0.2 electron volts. This effect was fully reversible and the band gap reduced back to zero under vacuum. The technique does not involve any complicated engineering or modification of the graphene, but requires an enclosure where humidity can be precisely controlled.

"Graphene is prized for its unique and attractive mechanical properties. But if you were to build a transistor using graphene, it simply wouldn't work as graphene acts like a semi-metal and has zero band gap," said Koratkar, a professor in the Department of Mechanical, Aerospace, and Nuclear Engineering at Rensselaer. "In this study, we demonstrated a relatively easy method for giving graphene a band gap. This could open the door to using graphene for a new generation of transistors, diodes, nanoelectronics, nanophotonics, and other applications."

Results of the study were detailed in the paper "Tunable Band gap in Graphene by the Controlled Adsorbtion of Water Molecules," published this week by the journal Small. See the full paper at: dx.doi.org/10.1002/smll.201001384

In its natural state, graphene has a peculiar structure but no band gap. It behaves as a metal and is known as a good conductor. This is compared to rubber or most plastics, which are insulators and do not conduct electricity. Insulators have a large band gap an energy gap between the valence and conduction bands which prevents electrons from conducting freely in the material.

Between the two are semiconductors, which can function as both a conductor and an insulator. Semiconductors have a narrow band gap, and application of an electric field can provoke electrons to jump across the gap. The ability to quickly switch between the two states "on" and "off" is why semiconductors are so valuable in microelectronics.

"At the heart of any semiconductor device is a material with a band gap," Koratkar said. "If you look at the chips and microprocessors in today's cell phones, mobile devices, and computers, each contains a multitude of transistors made from semiconductors with band gaps. Graphene is a zero band gap material, which limits its utility. So it is critical to develop methods to induce a band gap in graphene to make it a relevant semiconducting material."

The symmetry of graphene's lattice structure has been identified as a reason for the material's lack of band gap. Koratkar explored the idea of breaking this symmetry by binding molecules to only one side of the graphene. To do this, he fabricated graphene on a surface of silicon and silicon dioxide, and then exposed the graphene to an environmental chamber with controlled humidity. In the chamber, water molecules adsorbed to the exposed side of the graphene, but not on the side facing the silicon dioxide. With the symmetry broken, the band gap of graphene did, indeed, open up, Koratkar said. Also contributing to the effect is the moisture interacting with defects in the silicon dioxide substrate.

"Others have shown how to create a band gap in graphene by adsorbing different gasses to its surface, but this is the first time it has been done with water," he said. "The advantage of water adsorption, compared to gasses, is that it is inexpensive, nontoxic, and much easier to control in a chip application. For example, with advances in micro-packaging technologies it is relatively straightforward to construct a small enclosure around certain parts or the entirety of a computer chip in which it would be quite easy to control the level of humidity."

Based on the humidity level in the enclosure, chip makers could reversibly tune the band gap of graphene to any value from 0 to 0.2 electron volts, Korarkar said.

Along with Koratkar, authors on the paper are Theodorian Borca-Tasciuc, associate professor in the Department of Mechanical, Aerospace, and Nuclear Engineering at Rensselaer; Rensselaer mechanical engineering graduate student Fazel Yavari, who was first author on the paper; Rensselaer Focus Center New York Postdoctoral Research Associate Churamani Gaire; and undergraduate student Christo Kritzinger. Co-authors from Rice University are Professor Pulickel M. Ajayan; Postdoctoral Research Fellow Li Song; and graduate student Hemtej Gulapalli.

This study was supported by the Advanced Energy Consortium (AEC), National Institute of Standards and Technology (NIST) Nanoelectronics Research Initiative, and the U.S. Department of Energy Office of Basic Energy Sciences (BES).

For more information on Koratkar's graphene research at Rensselaer, visit:

Graphene Outperforms Carbon Nanotubes for Creating Stronger, More Crack-Resistant Materials news.rpi.edu/update.do?artcenterkey=2715

Rensselaer Researchers Secure $1 Million Grant To Develop Oil Exploration Game-Changer news.rpi.edu/update.do?artcenterkey=2700

Helping Hydrogen: Student Inventor Tackles Challenge of Hydrogen Storage
news.rpi.edu/update.do?artcenterkey=2690

Koratkar also was recently appointed as the editor of the journal Carbon: www.elsevier.com/wps/find/P10.cws_home/carbon_neweditors

####

For more information, please click here

Contacts:
Michael Mullaney
Phone: (518) 276-6161

Copyright © Rensselaer Polytechnic Institute

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

Personal cooling units on the horizon April 29th, 2016

Exploring phosphorene, a promising new material April 29th, 2016

Arrowhead Pharmaceuticals Files for Regulatory Clearance to Begin Phase 1/2 Study of ARC-521 April 28th, 2016

The Translational Research Center at the University Hospital of Erlangen in Germany uses the ZetaView from Particle Metrix to quantify extracellular vesicles such as exosomes April 28th, 2016

Govt.-Legislation/Regulation/Funding/Policy

Personal cooling units on the horizon April 29th, 2016

Exploring phosphorene, a promising new material April 29th, 2016

Nanoparticles hold promise as double-edged sword against genital herpes April 28th, 2016

Arrowhead Pharmaceuticals Files for Regulatory Clearance to Begin Phase 1/2 Study of ARC-521 April 28th, 2016

Possible Futures

Personal cooling units on the horizon April 29th, 2016

Exploring phosphorene, a promising new material April 29th, 2016

Researchers create a first frequency comb of time-bin entangled qubits: Discovery is a significant step toward multi-channel quantum communication and higher capacity quantum computers April 28th, 2016

Hybrid nanoantennas -- next-generation platform for ultradense data recording April 28th, 2016

Academic/Education

JPK reports on the use of a NanoWizard AFM system at the University of Kaiserslautern to study the interaction of bacteria with microstructured surfaces April 28th, 2016

The Ottawa Hospital Research Institute uses the ZetaView from Particle Metrix to study membrane microparticles as potential biomarkers for underlying diseases April 12th, 2016

FEI Partners with Five Pharmaceutical Companies, the Medical Research Council and the University of Cambridge to form Cryo-EM Research Consortium April 5th, 2016

SUNY Poly, in Collaboration with the George Washington School of Medicine and Health Sciences and Stony Brook University, Demonstrates Pioneering Method to Visualize and Identify Engineered Nanoparticles in Tissue March 25th, 2016

Chip Technology

Exploring phosphorene, a promising new material April 29th, 2016

Researchers create a first frequency comb of time-bin entangled qubits: Discovery is a significant step toward multi-channel quantum communication and higher capacity quantum computers April 28th, 2016

University of Illinois researchers create 1-step graphene patterning method April 27th, 2016

NREL theory establishes a path to high-performance 2-D semiconductor devices April 27th, 2016

Nanotubes/Buckyballs/Fullerenes

NREL finds nanotube semiconductors well-suited for PV systems April 27th, 2016

Researchers create artificial protein to control assembly of buckyballs April 27th, 2016

Cleaning up hybrid battery electrodes improves capacity and lifespan: New way of building supercapacitor-battery electrodes eliminates interference from inactive components April 22nd, 2016

Nature Photonics: Light source for quicker computer chips: Waveguide with integrated carbon nanotubes for conversion of electric signals into light / quicker computer chips are feasible / publication in Nature Photonics April 21st, 2016

Nanoelectronics

Exploring phosphorene, a promising new material April 29th, 2016

Physicists build 'electronic synapses' for neural networks April 21st, 2016

With simple process, UW-Madison engineers fabricate fastest flexible silicon transistor April 21st, 2016

All powered up: UCI chemists create battery technology with off-the-charts charging capacity April 21st, 2016

Announcements

Personal cooling units on the horizon April 29th, 2016

Exploring phosphorene, a promising new material April 29th, 2016

Arrowhead Pharmaceuticals Files for Regulatory Clearance to Begin Phase 1/2 Study of ARC-521 April 28th, 2016

The Translational Research Center at the University Hospital of Erlangen in Germany uses the ZetaView from Particle Metrix to quantify extracellular vesicles such as exosomes April 28th, 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