Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Better together: Graphene-nanotube hybrid switches

04.08.2015

Graphene has been called a wonder material, capable of performing great and unusual material acrobatics. Boron nitride nanotubes are no slackers in the materials realm either, and can be engineered for physical and biological applications.

However, on their own, these materials are terrible for use in the electronics world. As a conductor, graphene lets electrons zip too fast--there's no controlling or stopping them--while boron nitride nanotubes are so insulating that electrons are rebuffed like an overeager dog hitting the patio door.


Hair-like boron nitride nanotubes intersect a sheet of graphene to create a digital switch.

Credit: Michigan Tech, Yoke Khin Yap

But together, these two materials make a workable digital switch, which is the basis for controlling electrons in computers, phones, medical equipment and other electronics.

Yoke Khin Yap, a professor of physics at Michigan Technological University, has worked with a research team that created these digital switches by combining graphene and boron nitride nanotubes. The journal Scientific Reports recently published their work.

"The question is: How do you fuse these two materials together?" Yap says. The key is in maximizing their existing chemical structures and exploiting their mismatched features.

Nanoscale Tweaks

Graphene is a molecule-thick sheet of carbon atoms; the nanotubes are like straws made of boron and nitrogen. Yap and his team exfoliate graphene and modify the material's surface with tiny pinholes. Then they can grow the nanotubes up and through the pinholes. Meshed together like this, the material looks like a flake of bark sprouting erratic, thin hairs.

"When we put these two aliens together, we create something better," Yap says, explaining that it's important that the materials have lopsided band gaps, or differences in how much energy it takes to excite an electron in the material. "When we put them together, you form a band gap mismatch--that creates a so-called 'potential barrier' that stops electrons."

The band gap mismatch results from the materials' structure: graphene's flat sheet conducts electricity quickly, and the atomic structure in the nanotubes halts electric currents. This disparity creates a barrier, caused by the difference in electron movement as currents move next to and past the hair-like boron nitride nanotubes. These points of contact between the materials--called heterojunctions--are what make the digital on/off switch possible.

"Imagine the electrons are like cars driving across a smooth track," Yap says. "They circle around and around, but then they come to a staircase and are forced to stop."

Yap and his research team have also shown that because the materials are respectively so effective at conducting or stopping electricity, the resulting switching ratio is high. In other words, how fast the materials can turn on and off is several orders of magnitude greater than current graphene switches. In turn, this speed could eventually quicken the pace of electronics and computing.

Solving the Semiconductor Dilemma

To get to faster and smaller computers one day, Yap says this study is a continuation of past research into making transistors without semiconductors. The problem with semiconductors like silicon is that they can only get so small, and they give off a lot of heat; the use of graphene and nanotubes bypasses those problems. In addition, the graphene and boron nitride nanotubes have the same atomic arrangement pattern, or lattice matching. With their aligned atoms, the graphene-nanotube digital switches could avoid the issues of electron scattering.

"You want to control the direction of the electrons," Yap explains, comparing the challenge to a pinball machine that traps, slows down and redirects electrons. "This is difficult in high speed environments, and the electron scattering reduces the number and speed of electrons."

Much like an arcade enthusiast, Yap says he and his team will continue trying to find ways to outsmart or change the pinball set-up of graphene to minimize electron scattering. And one day, all their tweaks could make for faster computers--and digital pinball games--for the rest of us.

Media Contact

Yoke Khin Yap
ykyap@mtu.edu
906-487-2900

 @michigantech

http://www.mtu.edu 

Yoke Khin Yap | EurekAlert!

More articles from Materials Sciences:

nachricht Using a simple, scalable method, a material that can be used as a sensor is developed
15.02.2017 | University of the Basque Country

nachricht New mechanical metamaterials can block symmetry of motion, findings suggest
14.02.2017 | University of Texas at Austin

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Biocompatible 3-D tracking system has potential to improve robot-assisted surgery

17.02.2017 | Medical Engineering

Real-time MRI analysis powered by supercomputers

17.02.2017 | Medical Engineering

Antibiotic effective against drug-resistant bacteria in pediatric skin infections

17.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>