Rational Design of Nanomaterials Takes a Step Forward

Observation supports theory that nanoparticles act as artificial atoms in crystal growth

2 min read

Measuring, characterizing, and manipulating at the nanoscale are foundational elements of nanotechnology. And this week we’ve seen in news from IBM just how important improving microscopy is to all that.

Now researchers at the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have used transmission electron microscopy and advanced liquid cell handling to see if they could gather evidence to support the controversial theory that nanoparticles act as artificial atoms during the growth of crystals.

“We observed that as nanoparticles become attached they initially form winding polycrystalline chains,” says Haimei Zheng, a staff scientist in Berkeley Lab’s Materials Sciences Division in a press release. “These chains eventually align and attach end-to-end to form nanowires that straighten and stretch into single crystal nanorods with length-to-thickness ratios up to 40:1. This nanocrystal growth process, whereby nanoparticle chains as well as nanoparticles serve as the fundamental building blocks for nanorods, is both smart and efficient.”

You can see this process quite clearly in the video:

The research, which was published last week in the journal Science, observed the nanoparticles “undergo continuous rotation and interaction until they find a perfect lattice match. A sudden jump to contact then occurs over less than 1 nanometer, followed by lateral atom-by-atom addition initiated at the contact point.”

This observation and understanding of how nanoparticles make up crystal growth will likely provide important insight into the design of nanomaterials.

“From what we observed only single nanoparticles exist at the beginning of crystal growth, but, as growth proceeds, small chains of nanoparticles become dominant until, ultimately, only long chains of nanoparticles can be seen,” Zheng says. “Our observations provide a link between the world of single molecules and hierarchical nanostructures, paving the way for the rational design of nanomaterials with controlled properties.”

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Emily Cooper

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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