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More versatile wearable tech not bound by semiconductors thanks to ‘quantum tunneling’


[Image above] Credit: David Goehring, Flickr CC BY 2.0 

We might actually want to start wearing wearables.

From high-tech smart fashion to bracelets that track your mood to the newest augmented reality devices, wearables will get more sophisticated this year. The 2016 Consumer Electronics Show in Las Vegas last month debuted the latest wearable technologies with features like low energy Bluetooth, cloud computing, 3-D printing, and flexible membranes that will transform this market.

At the end of December, scientists at the University of Manitoba in Canada developed a unique sensing device made of chewing gum and carbon nanotubes that can move and bend with your body and still accurately track vitals like your breathing.

Netflix launched a kit around the holidays for ambitious do-it-yourselfers to assemble their own pair of cozy, cute socks that detect when they’ve fallen asleep and pause their program so they don’t miss any of the action.

Earlier this week engineers at the University of California, Berkeley released news that they developed a prototype for a flexible, wearable sensor system that can measure metabolites and electrolytes in sweat, calibrate the data based on skin temperature, and sync the results in real time to a smartphone.

But the most recent innovation in wearable tech so far this year is pushing the boundaries of electronics hardware.

Researchers at Michigan Technological University (Houghton, Mich.) are “revamping the fundamental base of transistors and creating a series of stepping-stones that use an electron movement called ‘quantum tunneling,’” according to a university news release.

Specifically, the researchers say that quantum dots of iron arranged on boron nitride nanotubes—also know as BNNTs—could be the key to moving beyond the more traditional semiconductor technology widely used in most wearable tech devices.

“Look beyond semiconductors,” Yoke Khin Yap, professor of physics at Michigan Technological University, says in the release.

According to Yap, materials like silicon semiconductors have limitations to how small they can get, and they tend to overheat and leak electric current, which makes them less efficient.

With quantum tunneling, there’s no resistance like you get when you use semiconductors—and that means no heat is generated, the release explains. And BNNTs’ incredibly tiny size and flexibility enables a smaller transistor that makes sense for wearables.

Here’s how it works:

Nanotubes make up the mainframe of BNNTs—and while the materials are fantastic insulators, they aren’t great conductors. But it’s actually the insulating effect of BNNTs that’s crucial to prevent electricity leakage and overheating, the release explains. Electron flow only occurs across the metal quantum dots placed on the BNNTs.

In the past, Yap and his team used gold for quantum dots, placed along a BNNT in a tidy line.

“Imagine this as a river, and there’s no bridge; it’s too big to hop over,” Yap says in the release. “Now, picture having stepping stones across the river—you can cross over, but only when you have enough energy to do so.”

Credit: Michigan Technological University, YouTube

In their latest research, they’re using iron-dotted boron nitride nanotubes to better withstand the high temperatures used in their experiments and provide more paths for electrons to travel.

“This time we used iron instead of gold,” Yap says, explaining that gold’s melting temperature was too low for the process his team used. “And when we tested the material, the electrons distributed uniformly across the whole surface of the nanotubes.”

So instead being limited to a “tidy line of stones,” the iron quantum dots enable multiple paths for the electrons to travel.

“For future use in wearable electronics, the multiplicity of paths ensures electricity is moving from one riverbank to the next, one way or another,” the release explains.

Yap and his team say that while the iron BNNT material shows promise, it hasn’t reach “full transistor status” yet, capable of modulating electron movement. But the plan is to put the material to the bend test.

“Next, we’ll put the BNNT and iron onto a bendable plastic substrate,” Yap says. “Then we’ll bend this substrate and watch where the electrons go.”

The study will be published later this month in Scientific Reports.