Mar 18, 2019 | |
Researchers discover new material to help power electronics(Nanowerk News) Electronics rule our world, but electrons rule our electronics. |
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A research team at The Ohio State University has discovered a way to simplify how electronic devices use those electrons—using a material that can serve dual roles in electronics, where historically multiple materials have been necessary. | |
The team published its findings in the journal Nature Materials ("The Fermi surface geometrical origin of axis-dependent conduction polarity in layered materials"). | |
“We have essentially found a dual-personality material,” said Joseph Heremans, co-author of the study, professor of mechanical and aerospace engineering and Ohio Eminent Scholar in Nanotechnology at Ohio State. “It is a concept that did not exist before.” | |
Their findings could mean a revamp of the way engineers create all different kinds of electronic devices. This includes everything from solar cells, to the light-emitting diodes in your television, to the transistors in your laptop, and to the light sensors in your smartphone camera. | |
Those devices are the building blocks of electricity: Each electron has a negative charge and can radiate or absorb energy depending on how it is manipulated. Holes—essentially, the absence of an electron—have a positive charge. Electronic devices work by moving electrons and holes—essentially conducting electricity. | |
But historically, each part of the electronic device could only act as electron-holder or a hole-holder, not both. That meant that electronics needed multiple layers—and multiple materials—to perform. | |
But the Ohio State researchers found a material – NaSn2As2, a crystal that can be both electron-holder and hole-holder – potentially eliminating the need for multiple layers. | |
“It is this dogma in science, that you have electrons or you have holes, but you don’t have both. But our findings flip that upside down,” said Wolfgang Windl, a professor of materials science and engineering at Ohio State, and co-author of the study. “And it’s not that an electron becomes a hole, because it’s the same assembly of particles. Here, if you look at the material one way, it looks like an electron, but if you look another way, it looks like a hole.” | |
The finding could simplify our electronics, perhaps creating more efficient systems that operate more quickly and break down less often. | |
Think of it like a Rube Goldberg machine, or the 1960s board game Mouse Trap: the more pieces at play and the more moving parts, the less efficiently energy travels throughout the system—and the more likely something is to fail. | |
“Now, we have this new family of layered crystals where the carriers behave like electrons when traveling within each layer, and holes when traveling through the layers. … You can imagine there might be some unique electronic devices you could create,” said Joshua Goldberger, associate professor of chemistry and biochemistry at Ohio State. | |
The researchers named this dual-ability phenomenon “goniopolarity.” They believe the material functions this way because of its unique electronic structure, and say it is probable that other layered materials could exhibit this property. | |
“We just haven’t found them yet,” Heremans said. “But now we know to search for them.” | |
The researchers made the discovery almost by accident. A graduate student researcher in Heremans’ lab, Bin He, was measuring the properties of the crystal when he noticed that the material behaved sometimes like an electron-holder and sometimes like a hole-holder—something that, at that point, science thought was impossible. He thought perhaps he had made an error, ran the experiment again and again, and got the same result. | |
“It was this thing that he paid attention and he didn’t assume anything,” Heremans said. | |
Bin He has since accepted a postdoctorate position at the Max Planck Institute in Dresden, Germany. |
Source: By Laura Arenschield, Ohio State University | |
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