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CHS Grad Jimmy Custer Heads Research Efforts on Technological Breakthrough, Serves as Lead Author in “Science” Article

CHS Grad Jimmy Custer With 2011 Cheltenham graduate Jimmy Custer serving as the lead author, researchers at the University of North Carolina - Chapel Hill published the article “Ratcheting quasi-ballistic electrons in silicon geometric diodes at room temperature” in the April 10 edition of Science about the ability of devices to process ultra-high-speed wireless data while also harvesting energy for power. 

“This work is exciting because it could enable a future where things like low-power smartwatches are wirelessly charged from the data they already receive without ever needing to leave a person’s wrist,” said Custer, a fifth-year doctoral student in UNC-Chapel Hill’s College of Arts & Sciences. He collaborated on the project with researchers from Duke and Vanderbilt universities.

The research team shaped silicon on a microscopic scale to create a funnel or “ratchet” for electrons, effectively forcing them down “a one-way street.” This method overcame the speed limitations of prior technologies by removing interfaces that tend to slow devices. 

“We are using the shape of a nanomaterial to control the direction electrons flow,” Custer added. “In my group, we can design silicon nanowires that are shaped like funnels. Because of the wires’ size, electrons inside act like billiard balls, bouncing off the walls. Then the funnel shape forces the electron flow primarily in one direction of the nanowire. This turns these nanowires into one of the fundamental elements for circuitry and computation – a diode.”

Diodes are used billions of times daily to process data in all technology, but due to the physics of traditional diodes, the speed at which they can process data is limited. The diode mechanism Custer’s team developed is new and fundamentally different from standard diodes. The improved properties of the new diode include greatly increased data processing speeds (potentially 100x-1000x Wi-Fi) and the ability to harvest energy from the data that is being sent to a device. This new type of geometric diode may lead to even faster circuitry for high-speed communication.

Prior examples of geometric diodes needed expensive materials and/or to be cooled to cryogenic temperatures. Custer et. al.’s geometric diodes work at room temperature and are made with relatively cheap silicon (the same material as computer chips), easing the integration into current technology.

Science has been at the center of important scientific discovery since its founding in 1880 — with seed money from Thomas Edison. Today, Science continues to publish the very best in research across the sciences, with articles that consistently rank among the most cited in the world. In the last half century alone, Science published the entire human genome for the first time; never-before seen images of the Martian surface; and the first studies tying AIDS to human immunodeficiency virus.