Small Tweaks to Its Recipe and "White Graphene" Could Change Electronics

Adding some small twists to chemical vapor deposition makes a hexagonal boron nitride that could make the perfect substrate for graphene

2 min read
Small Tweaks to Its Recipe and "White Graphene" Could Change Electronics
Structural characterization of hBN. Schematic illustration of a hBN monolayer.
Illustration: ORNL/Nature Nanotechnology

Strictly speaking, hexagonal boron nitride is a semiconductor, but its band gap is so big that, for all practical purposes, it behaves like an insulator.

It’s because of this pseudo-insulator characteristic that researchers have been interested in combining boron nitride with other two-dimensional materials such as graphene to create hybrid materials capable of doing what each constituent can’t do on its own.

Now researchers at the Department of Energy’s Oak Ridge National Laboratory (ORNL) have developed a process for producing a nearly perfect single layer of hexagonal boron nitride—dubbed “white graphene”—that the researchers believe could be a game changer for the use of the material in electronic applications.

In research published in the journal Chemistry of Materials, the ORNL researchers followed traditional chemical vapor deposition (CVD) steps, in which gaseous reactants are introduced into a furnace to form a film on a metal substrate that’s usually made of copper. However, they added a little something to the recipe that provided a more gentle and controllable way to introduce the reactants into the furnace and took better advantage of the conditions inside the furnace.

“I just thought carefully beforehand and was curious. For example, I remind myself that there are many conditions in this experiment that can be adjusted and could make a difference,” said ORNL’s Yijing Stehle, postdoctoral associate and lead author of a paper, in a press release. “Whenever I see non-perfect results, I do not count them as another failure but, instead, another condition adjustment to be made. This ‘failure’ may become valuable.”

The result of finding value in failure was a “white graphene” that has lived up to the material’s previously unachieved theoretical performance potential. What this means is that if white graphene were used as a substrate material for its carbon analogue, the electron mobility of the combined materials would be a thousand times higher than that of graphene on other substrate materials.

“Imagine batteries, capacitors, solar cells, video screens and fuel cells as thin as a piece of paper,” said Stehle in the press release. “Imagine your message being sent thousands of times faster.”

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3D-Stacked CMOS Takes Moore’s Law to New Heights

When transistors can’t get any smaller, the only direction is up

10 min read
An image of stacked squares with yellow flat bars through them.
Emily Cooper
Green

Perhaps the most far-reaching technological achievement over the last 50 years has been the steady march toward ever smaller transistors, fitting them more tightly together, and reducing their power consumption. And yet, ever since the two of us started our careers at Intel more than 20 years ago, we’ve been hearing the alarms that the descent into the infinitesimal was about to end. Yet year after year, brilliant new innovations continue to propel the semiconductor industry further.

Along this journey, we engineers had to change the transistor’s architecture as we continued to scale down area and power consumption while boosting performance. The “planar” transistor designs that took us through the last half of the 20th century gave way to 3D fin-shaped devices by the first half of the 2010s. Now, these too have an end date in sight, with a new gate-all-around (GAA) structure rolling into production soon. But we have to look even further ahead because our ability to scale down even this new transistor architecture, which we call RibbonFET, has its limits.

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