Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Physicists decipher electronic properties of materials in work that may change transistors

Dr. Fan Zhang (right), assistant professor of physics, and senior physics student Armin Khamoshi recently published their research on transition metal dichalcogenides.
Dr. Fan Zhang (right), assistant professor of physics, and senior physics student Armin Khamoshi recently published their research on transition metal dichalcogenides.

Abstract:
University of Texas at Dallas physicists have published new findings examining the electrical properties of materials that could be harnessed for next-generation transistors and electronics.

Physicists decipher electronic properties of materials in work that may change transistors

Dallas, TX | Posted on December 6th, 2016

Dr. Fan Zhang, assistant professor of physics, and senior physics student Armin Khamoshi recently published their research on transition metal dichalcogenides, or TMDs, in the journal Nature Communications. Zhang is a co-corresponding author, and Khamoshi is a co-lead author of the paper, which also includes collaborating scientists at Hong Kong University of Science and Technology.

In recent years, scientists and engineers have become interested in TMDs in part because they are superior in many ways to graphene, a one-atom thick, two-dimensional sheet of carbon atoms arranged in a lattice. Since it was first isolated in 2004, graphene has been investigated for its potential to replace conventional semiconductors in transistors, shrinking them even further in size. Graphene is an exceptional conductor, a material in which electrons move easily, with high mobility.

"It was thought that graphene could be used in transistors, but in transistors, you need to be able to switch the electric current on and off," Zhang said. "With graphene, however, the current cannot be easily switched off."

Beyond Graphene

In their search for alternatives, scientists and engineers have turned to TMDs, which also can be made into thin, two-dimensional sheets, or monolayers, just a few molecules thick.

"TMDs have something graphene does not have -- an energy gap that allows the flow of electrons to be controlled, for the current to be switched on and off," Khamoshi said. "This gap makes TMDs ideal for use in transistors. TMDs are also very good absorbers of circularly polarized light, so they could be used in detectors. For these reasons, these materials have become a very popular topic of research."

One of the challenges is to optimize and increase electron mobility in TMD materials, a key factor if they are to be developed for use in transistors, Khamoshi said.

In their most recent project, Zhang and Khamoshi provided the theoretical work to guide the Hong Kong group on the layer-by-layer construction of a TMD device and on the use of magnetic fields to study how electrons travel through the device. Each monolayer of TMD is three molecules thick, and the layers were sandwiched between two sheets of boron nitride molecules.

The behavior of electrons controls the behavior of these materials," Zhang said. "We want to make use of highly mobile electrons, but it is very challenging. Our collaborators in Hong Kong made significant progress in that direction by devising a way to significantly increase electron mobility."

The team discovered that how electrons behave in the TMDs depends on whether an even or odd number of TMD layers were used.

"This layer-dependent behavior is a very surprising finding," Zhang said. "It doesn't matter how many layers you have, but rather, whether there are an odd or even number of layers."

Electron Physics

Because the TMD materials operate on the scale of individual atoms and electrons, the researchers incorporated quantum physics into their theories and observations. Unlike classical physics, which describes the behavior of large-scale objects that we can see and touch, quantum physics governs the realm of very small particles, including electrons.

On the size scale of everyday electrical devices, electrons flowing through wires behave like a stream of particles. In the quantum world, however, electrons behave like waves, and the electrical transverse conductance of the two-dimensional material in the presence of a magnetic field is no longer like a stream -- it changes in discrete steps, Zhang said. The phenomenon is called quantum Hall conductance.

"Quantum Hall conductance might change one step by one step, or two steps by two steps, and so on," he said. "We found that if we used an even number of TMD layers in our device, there was a 12-step quantum conductance. If we applied a strong enough magnetic field to it, it would change by six steps at a time."

Using an odd number of layers combined with a low magnetic field also resulted in a 6-step quantum Hall conductance in the TMDs, but under stronger magnetic fields, it became a 3-step by 3-step phenomenon.

"The type of quantum Hall conductance we predicted and observed in our TMD devices has never been found in any other material," Zhang said. "These results not only decipher the intrinsic properties of TMD materials, but also demonstrate that we achieved high electron mobility in the devices. This gives us hope that we can one day use TMDs for transistors."

###

The research was supported in part by the National Science Foundation, UT Dallas Research Enhancement Funds and UT Dallas Undergraduate Research Scholar Awards.

####

For more information, please click here

Contacts:
Amanda Siegfried

972-883-4335

Copyright © University of Texas at Dallas

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

RELATED JOURNAL ARTICLE:

Related News Press

Quantum Physics

'Find the Lady' in the quantum world: International team of researchers presents method for quantum-mechanical swapping of positions October 18th, 2017

What can be discovered at the junction of physics and chemistry October 6th, 2017

Energy against the current on a quantum scale, without contradicting the laws of physics: A piece of research in which the UPV/EHU-University of the Basque Country has participated confirms that merely observing a flow of energy or particles can change its direction October 6th, 2017

Quantum communications bend to our needs: By changing the wavelengths of entangled photons to those used in telecommunications, researchers see quantum technology take a major leap forward September 28th, 2017

Enhancing the sensing capabilities of diamonds with quantum properties: A simple method can give diamonds the special properties needed for quantum applications such as sensing magnetic fields September 24th, 2017

News and information

'Find the Lady' in the quantum world: International team of researchers presents method for quantum-mechanical swapping of positions October 18th, 2017

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

Spin current detection in quantum materials unlocks potential for alternative electronics October 15th, 2017

2 Dimensional Materials

Injecting electrons jolts 2-D structure into new atomic pattern: Berkeley Lab study is first to show potential of energy-efficient next-gen electronic memory October 13th, 2017

Rice U. lab surprised by ultraflat magnets: Researchers create atom-thick alloys with unanticipated magnetic properties October 13th, 2017

Two dimensional materials: Advanced molybdenum selenide near infrared phototransistors September 27th, 2017

Hardware

Tungsten offers nano-interconnects a path of least resistance: Crystalline tungsten shows insight and promise in addressing the challenges of electrical interconnects that have high resistivity at the nanoscale October 4th, 2017

A Sea of Spinning Electrons: Rutgers-led discovery could spawn a wave of new electronic devices October 2nd, 2017

Magnetism

Fast-moving magnetic particles could enable new form of data storage: Recently discovered phenomenon could provide a way to bypass the limits to Moore's Law October 2nd, 2017

Assembly of nanoparticles proceeds like a zipper: Viruses and nanoparticles can be assembled into processable superlattice wires according to scientists from Aalto University Finland September 25th, 2017

Enhancing the sensing capabilities of diamonds with quantum properties: A simple method can give diamonds the special properties needed for quantum applications such as sensing magnetic fields September 24th, 2017

Graphene/ Graphite

Graphene forged into three-dimensional shapes September 26th, 2017

Govt.-Legislation/Regulation/Funding/Policy

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

Rice U. study: Vibrating nanoparticles interact: Placing nanodisks in groups can change their vibrational frequencies October 16th, 2017

Spin current detection in quantum materials unlocks potential for alternative electronics October 15th, 2017

Possible Futures

'Find the Lady' in the quantum world: International team of researchers presents method for quantum-mechanical swapping of positions October 18th, 2017

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

Rice U. study: Vibrating nanoparticles interact: Placing nanodisks in groups can change their vibrational frequencies October 16th, 2017

Chip Technology

Spin current detection in quantum materials unlocks potential for alternative electronics October 15th, 2017

Quantum manipulation power for quantum information processing gets a boost: Improving the efficiency of quantum heat engines involves reducing the number of photons in a cavity, ultimately impacting quantum manipulation power October 14th, 2017

Injecting electrons jolts 2-D structure into new atomic pattern: Berkeley Lab study is first to show potential of energy-efficient next-gen electronic memory October 13th, 2017

Rice U. lab surprised by ultraflat magnets: Researchers create atom-thick alloys with unanticipated magnetic properties October 13th, 2017

Nanoelectronics

Nanometrics Announces Preliminary Results for the Third Quarter of 2017: Quarterly Results Impacted by Delays in Revenue Recognition on Multiple Systems into Japan October 12th, 2017

Seeing the next dimension of computer chips: Researchers image perfectly smooth side-surfaces of 3-D silicon crystals with a scanning tunneling microscope, paving the way for smaller and faster computing devices October 11th, 2017

Columbia engineers invent breakthrough millimeter-wave circulator IC October 6th, 2017

Tungsten offers nano-interconnects a path of least resistance: Crystalline tungsten shows insight and promise in addressing the challenges of electrical interconnects that have high resistivity at the nanoscale October 4th, 2017

Discoveries

'Find the Lady' in the quantum world: International team of researchers presents method for quantum-mechanical swapping of positions October 18th, 2017

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

Rice U. study: Vibrating nanoparticles interact: Placing nanodisks in groups can change their vibrational frequencies October 16th, 2017

Materials/Metamaterials

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Injecting electrons jolts 2-D structure into new atomic pattern: Berkeley Lab study is first to show potential of energy-efficient next-gen electronic memory October 13th, 2017

The secret to improving liquid crystal's mechanical performance: Better lubricating properties of lamellar liquid crystals could stem from changing the mobility of their structural dislocations by adding nanoparticles October 13th, 2017

Rice U. lab surprised by ultraflat magnets: Researchers create atom-thick alloys with unanticipated magnetic properties October 13th, 2017

Announcements

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

Rice U. study: Vibrating nanoparticles interact: Placing nanodisks in groups can change their vibrational frequencies October 16th, 2017

Spin current detection in quantum materials unlocks potential for alternative electronics October 15th, 2017

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

'Find the Lady' in the quantum world: International team of researchers presents method for quantum-mechanical swapping of positions October 18th, 2017

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

Rice U. study: Vibrating nanoparticles interact: Placing nanodisks in groups can change their vibrational frequencies October 16th, 2017

Grants/Sponsored Research/Awards/Scholarships/Gifts/Contests/Honors/Records

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Rice U. study: Vibrating nanoparticles interact: Placing nanodisks in groups can change their vibrational frequencies October 16th, 2017

On the road to fire-free, lithium-ion batteries made with asphalt October 12th, 2017

Single ‘solitons’ promising for optical technologies October 9th, 2017

Quantum nanoscience

'Find the Lady' in the quantum world: International team of researchers presents method for quantum-mechanical swapping of positions October 18th, 2017

What can be discovered at the junction of physics and chemistry October 6th, 2017

Energy against the current on a quantum scale, without contradicting the laws of physics: A piece of research in which the UPV/EHU-University of the Basque Country has participated confirms that merely observing a flow of energy or particles can change its direction October 6th, 2017

Enhancing the sensing capabilities of diamonds with quantum properties: A simple method can give diamonds the special properties needed for quantum applications such as sensing magnetic fields September 24th, 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