Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Material world: graphene’s versatility promises new applications

N.J. Tao, director of the Center for Bioelectronics and Biosensors, has experimentally measured an important property of graphene.
N.J. Tao, director of the Center for Bioelectronics and Biosensors, has experimentally measured an important property of graphene.

Abstract:
Since its discovery just a few years ago, graphene has climbed to the top of the heap of new super-materials poised to transform the electronics and nanotechnology landscape.

Material world: graphene’s versatility promises new applications

Tempe, AZ | Posted on August 6th, 2009

As N.J. Tao, a researcher at the Biodesign Institute of Arizona State University explains, this two-dimensional honeycomb structure of carbon atoms is exceptionally strong and versatile. Its unusual properties make it ideal for applications that are pushing the existing limits of microchips, chemical sensing instruments, biosensors, ultracapacitance devices, flexible displays and other innovations.

In the latest issue of Nature Nanotechnology Letters, Tao describes the first direct measurement of a fundamental property of graphene, known as quantum capacitance, using an electrochemical gate method. A better understanding of this crucial variable should prove invaluable to other investigators participating in what amounts to a gold rush of graphene research.

Although theoretical work on single atomic layer graphene-like structures has been going on for decades, the discovery of real graphene came as a shock. "When they found it was a stable material at room temperature," Tao says, "everyone was surprised." As it happens, minute traces of graphene are shed whenever a pencil line is drawn, though producing a 2-D sheet of the material has proven trickier. Graphene is remarkable in terms of thinness and resiliency. A one-atom thick graphene sheet sufficient in size to cover a football field, would weigh less than a gram. It is also the strongest material in nature—roughly 200 times the strength of steel. Most of the excitement however, has to do with the unusual electronic properties of the material.

Graphene displays outstanding electron transport, permitting electricity to flow rapidly and more or less unimpeded through the material. In fact, electrons have been shown to behave as massless particles similar to photons, zipping across a graphene layer without scattering. This property is critical for many device applications and has prompted speculation that graphene could eventually supplant silicon as the substance of choice for computer chips, offering the prospect of ultrafast computers operating at terahertz speeds, rocketing past current gigahertz chip technology. Yet, despite encouraging progress, a thorough understanding of graphene's electronic properties has remained elusive. Tao stresses that quantum capacitance measurements are an essential part of this understanding.

Capacitance is a material's ability to store energy. In classical physics, capacitance is limited by the repulsion of like electrical charges, for example, electrons. The more charge you put into a device, the more energy you have to expend to contain it, in order to overcome charge repulsion. However, another kind of capacitance exists, and dominates overall capacitance in a two-dimensional material like graphene. This quantum capacitance is the result of the Pauli exclusion principle, which states that two fermions—a class of common particles including protons, neutrons and electrons—cannot occupy the same location at the same time. Once a quantum state is filled, subsequent fermions are forced to occupy successively higher energy states. As Tao explains, "it's just like in a building, where people are forced to go to the second floor once the first level is occupied."

In the current study, two electrodes were attached to graphene, and a voltage applied across the material's two-dimensional surface by means of a third, gate electrode. Plots of voltage vs. capacitance can be seen in the figure above. In Tao's experiments, graphene's ability to store charge according to the laws of quantum capacitance, were subjected to detailed measurement. The results show that graphene's capacitance is very small. Further, the quantum capacitance of graphene did not precisely duplicate theoretical predictions for the behavior of ideal graphene. This is due to the fact that charged impurities occur in experimental samples of graphene, which alter the behavior relative to what is expected according to theory.

Tao stresses the importance of these charged impurities and what they may mean for the development of graphene devices. Such impurities were already known to affect electron mobility in graphene, though their effect on quantum capacitance has only now been revealed. Low capacitance is particularly desirable for chemical sensing devices and biosensors as it produces a lower signal-to-noise ratio, providing for extremely fine-tuned resolution of chemical or biological agents. Improvements to graphene will allow its electrical behavior to more closely approximate theory. This can be accomplished by adding counter ions to balance the charges resulting from impurities, thereby further lowering capacitance.

The sensitivity of graphene's single atomic layer geometry and low capacitance promise a significant boost for biosensor applications. Such applications are a central topic of interest for Tao, who directs the Biodesign Institute's Center for Bioelectronics and Biosensors. As Tao explains, any biological substance that interacts with graphene's single atom surface layer can be detected, causing a huge change in the properties of the electrons.

One possible biosensor application under consideration would involve functionalizing graphene's surface with antibodies, in order to precisely study their interaction with specific antigens. Such graphene-based biosensors could detect individual binding events, given a suitable sample. For other applications, adding impurities to graphene could raise overall interfacial capacitance. Ultracapacitors made of graphene composites would be capable of storing much larger amounts of renewable energy from solar, wind or wave energy than current technologies permit.

Because of graphene's planar geometry, it may be more compatible with conventional electronic devices than other materials, including the much-vaunted carbon nanotubes. "You can imagine an atomic sheet, cut into different shapes to create different device properties," Tao says.

Since the discovery of graphene, the hunt has been on for similar two-dimensional crystal lattices, though so far, graphene remains a precious oddity.

Advanced Online Publication: www.nature.com/nnano/journal/vaop/ncurrent/full/nnano.2009.177.html

####

About The Biodesign Institute, Arizona State University
The hundreds of researchers at ASU’s Biodesign Institute are driven by a passion to solve some of the world’s most urgent problems affecting human health and the health of our planet:

* Improving health care through more personalized diagnostics and treatment
* Providing renewable sources of energy and cleaning our environment
* Outpacing the global threat of infectious disease, including emerging diseases
* Securing a safer world, particularly through technology that detects threats in advance

For more information, please click here

Contacts:
Written by Richard Harth
Science Writer
Biodesign Institute

Copyright © The Biodesign Institute, Arizona State 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 News Press

News and information

In IEDM 2016 Keynote, Leti CEO Says ‘Hyperconnectivity’, Human-focused Research and the IOT Promise Profound, Positive Changes December 7th, 2016

Leti IEDM 2016 Paper Clarifies Correlation between Endurance, Window Margin and Retention in RRAM for First Time: Paper Presented at IEDM 2016 Offers Ways to Reconcile High-cycling Requirements and Instability at High Temperatures in Resistive RAM December 6th, 2016

Tokyo Institute of Technology research: 3D solutions to energy savings in silicon power transistors December 6th, 2016

Physicists decipher electronic properties of materials in work that may change transistors December 6th, 2016

Display technology/LEDs/SS Lighting/OLEDs

Trace metal recombination centers kill LED efficiency: UCSB researchers warn that trace amounts of transition metal impurities act as recombination centers in gallium nitride semiconductors November 3rd, 2016

Diamond nanothread: Versatile new material could prove priceless for manufacturing: Would you dress in diamond nanothreads? It's not as far-fetched as you might think November 3rd, 2016

Researchers surprised at the unexpected hardness of gallium nitride: A Lehigh University team discovers that the widely used semiconducting material is almost as wear-resistant as diamonds October 31st, 2016

Inspiration from the ocean: An interdisciplinary team of researchers at UC Santa Barbara has developed a non-toxic, high-quality surface treatment for organic field-effect transistors October 18th, 2016

Possible Futures

In IEDM 2016 Keynote, Leti CEO Says ‘Hyperconnectivity’, Human-focused Research and the IOT Promise Profound, Positive Changes December 7th, 2016

Physicists decipher electronic properties of materials in work that may change transistors December 6th, 2016

Fast, efficient sperm tails inspire nanobiotechnology December 5th, 2016

Construction of practical quantum computers radically simplified: Scientists invent ground-breaking new method that puts quantum computers within reach December 5th, 2016

Chip Technology

Leti IEDM 2016 Paper Clarifies Correlation between Endurance, Window Margin and Retention in RRAM for First Time: Paper Presented at IEDM 2016 Offers Ways to Reconcile High-cycling Requirements and Instability at High Temperatures in Resistive RAM December 6th, 2016

Tokyo Institute of Technology research: 3D solutions to energy savings in silicon power transistors December 6th, 2016

Physicists decipher electronic properties of materials in work that may change transistors December 6th, 2016

Construction of practical quantum computers radically simplified: Scientists invent ground-breaking new method that puts quantum computers within reach December 5th, 2016

Nanomedicine

Fast, efficient sperm tails inspire nanobiotechnology December 5th, 2016

Journal Nanotechnology Progress International (JONPI) Volume 6, issue 2 coming out soon! December 5th, 2016

UTSA study describes new minimally invasive device to treat cancer and other illnesses: Medicine diffusion capsule could locally treat multiple ailments and diseases over several weeks December 3rd, 2016

Nanobiotix Provides Update on Global Development of Lead Product NBTXR3: Seven clinical trials across the world: More than 2/3 of STS patients recruited in the “act.in.sarc” Phase II/III trial: Phase I/II prostate cancer trial now recruiting in the U.S. November 28th, 2016

Sensors

Shape matters when light meets atom: Mapping the interaction of a single atom with a single photon may inform design of quantum devices December 4th, 2016

Deep insights from surface reactions: Researchers use Stampede supercomputer to study new chemical sensing methods, desalination and bacterial energy production December 2nd, 2016

Tip-assisted chemistry enables chemical reactions at femtoliter scale November 16th, 2016

'Back to the Future' inspires solar nanotech-powered clothing November 15th, 2016

Nanoelectronics

Leti IEDM 2016 Paper Clarifies Correlation between Endurance, Window Margin and Retention in RRAM for First Time: Paper Presented at IEDM 2016 Offers Ways to Reconcile High-cycling Requirements and Instability at High Temperatures in Resistive RAM December 6th, 2016

Physicists decipher electronic properties of materials in work that may change transistors December 6th, 2016

Journal Nanotechnology Progress International (JONPI) Volume 6, issue 2 coming out soon! December 5th, 2016

Supersonic spray yields new nanomaterial for bendable, wearable electronics: Film of self-fused nanowires clear as glass, conducts like metal November 23rd, 2016

Materials/Metamaterials

Physicists decipher electronic properties of materials in work that may change transistors December 6th, 2016

Infrared instrumentation leader secures exclusive use of Vantablack coating December 5th, 2016

Construction of practical quantum computers radically simplified: Scientists invent ground-breaking new method that puts quantum computers within reach December 5th, 2016

Inside tiny tubes, water turns solid when it should be boiling: MIT researchers discover astonishing behavior of water confined in carbon nanotubes November 30th, 2016

Announcements

In IEDM 2016 Keynote, Leti CEO Says ‘Hyperconnectivity’, Human-focused Research and the IOT Promise Profound, Positive Changes December 7th, 2016

Leti IEDM 2016 Paper Clarifies Correlation between Endurance, Window Margin and Retention in RRAM for First Time: Paper Presented at IEDM 2016 Offers Ways to Reconcile High-cycling Requirements and Instability at High Temperatures in Resistive RAM December 6th, 2016

Tokyo Institute of Technology research: 3D solutions to energy savings in silicon power transistors December 6th, 2016

Physicists decipher electronic properties of materials in work that may change transistors December 6th, 2016

Energy

Research Study: MetaSOLTM Shatters Solar Panel Efficiency Forecasts with Innovative New Coating: Coating Provides 1.2 Percent Absolute Enhancement to Triple Junction Solar Cells December 2nd, 2016

Deep insights from surface reactions: Researchers use Stampede supercomputer to study new chemical sensing methods, desalination and bacterial energy production December 2nd, 2016

Throwing new light on printed organic solar cells December 1st, 2016

Physics, photosynthesis and solar cells: Researchers combine quantum physics and photosynthesis to make discovery that could lead to highly efficient, green solar cells November 30th, 2016

Battery Technology/Capacitors/Generators/Piezoelectrics/Thermoelectrics/Energy storage

Novel Electrode Structure Provides New Promise for Lithium-Sulfur Batteries December 3rd, 2016

A Phone That Charges in Seconds? UCF Scientists Bring it Closer to Reality November 21st, 2016

'Back to the Future' inspires solar nanotech-powered clothing November 15th, 2016

Vesper a Finalist for Two ACE Awards: Ultimate Products and Innovator of the Year -- Industry’s first piezoelectric MEMS microphone and Vesper CTO Bobby Littrell recognized for prestigious electronics-industry awards November 10th, 2016

Nanobiotechnology

Fast, efficient sperm tails inspire nanobiotechnology December 5th, 2016

Deep insights from surface reactions: Researchers use Stampede supercomputer to study new chemical sensing methods, desalination and bacterial energy production December 2nd, 2016

Nanobiotix Provides Update on Global Development of Lead Product NBTXR3: Seven clinical trials across the world: More than 2/3 of STS patients recruited in the “act.in.sarc” Phase II/III trial: Phase I/II prostate cancer trial now recruiting in the U.S. November 28th, 2016

From champagne bubbles, dance parties and disease to new nanomaterials: Understanding nucleation of protein filaments might help with Alzheimer's Disease and type 2 Diabetes November 24th, 2016

Solar/Photovoltaic

Research Study: MetaSOLTM Shatters Solar Panel Efficiency Forecasts with Innovative New Coating: Coating Provides 1.2 Percent Absolute Enhancement to Triple Junction Solar Cells December 2nd, 2016

Throwing new light on printed organic solar cells December 1st, 2016

Physics, photosynthesis and solar cells: Researchers combine quantum physics and photosynthesis to make discovery that could lead to highly efficient, green solar cells November 30th, 2016

'Back to the Future' inspires solar nanotech-powered clothing November 15th, 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