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Student examines sample in Chu's lab

Wide bandgap semiconductors such as gallium nitride are better for radio frequency and power electronics. Credit: Jennifer M. McCann/Penn State MRI

By Jamie Oberdick

Your cellphone probably would not work very well in space. That is because outer space is full of radiation, and radiation causes defects in electronics that can eventually lead to device failure. You and your cellphone are likely not going to be in outer space anytime soon, but if you are an astronaut relying on electronics to get you to and from space without incident, Rongming Chu’s research may one day be key in keeping you safe.

Chu, associate professor of electrical engineering at Penn State, leads research on advancing semiconductors toward extreme capabilities. These capabilities include high operating speeds, high-power handling, and ability to withstand harsh environments, such as the radiation-filled, electronics-hostile realm of outer space.

“Our research largely leverages a relatively new semiconductor material called gallium nitride,” Chu said. “Gallium nitride is being used in today’s LEDs, 4G base stations, and increasingly in fast battery chargers. My group focuses on new devices and integration technology to take their performance to the next level.”

Wide bandgap semiconductors such as gallium nitride are better for radio frequency and power electronics than the material used in most of today’s semiconductors, silicon. They are also high in a particular characteristic, radiation hardness, that protects against damage caused by radiation from high-energy rays and particles. Therefore, these wide bandgap semiconductors are especially useful for electronics operating in high-radiation environments, without requiring cumbersome radiation shielding.

In July 2022, Chu led a collaboration with the University of Central Florida, Carnegie Mellon University, and the University of Iowa that received a $7.5 million Defense Multidisciplinary University Research Initiative Award from the U.S. Department of Defense’s Air Force Office of Scientific Research. This group included from Penn State Patrick M. Lenahan, distinguished professor of engineering science and mechanics; Miaomiao Jin, assistant professor of nuclear engineering; and Blair R. Tuttle, professor of physics.

“Our research will benefit a lot from collaborations within Penn State, and elsewhere in America,” Chu said.

While Chu’s research is valuable for America’s space program, there is related on-going research that will benefit those of us earth-bound people.

“In addition to the radiation hardness research, we are working on high-power switches targeting applications in power grids, electric aircraft, and electric ships. This research, supported by the Advanced Research Project Agency – Energy under the Department of Energy and the Office of Naval Research under the Department of Defense, will help us to get more reliable access to the power grid, to use energy more efficiently, and to reduce our reliance on fossil-energy,” Chu said.

While this research would lead to applications directly benefiting American society, Chu sees Penn State’s role in developing America’s semiconductor future as multi-faceted.

"We will contribute to increasing America’s role in the future of semiconductors development and production by firstly, creating and maintaining a research/education environment that attracts the best talent from the world,” Chu said. “Secondly, developing innovative technologies that have a real path towards market adoption, and thirdly, training the next-generation technologists who will lead continued innovation of semiconductors.”


This article originally appeared in the Fall 2022 issue of Focus on Materials.