KINGSVILLE (August 26, 2024) — Two electrical engineering professors from Texas A&M University-Kingsville are making waves with tiny things and ultra-low temperatures. Drs. Reza Nekovei and Amit Verma, professors in the electrical engineering and computer science department in the Frank H. Dotterweich College of Engineering, recently had a paper published in the IEEE Transactions on Nanotechnology, a renowned journal in the field.
Their paper Low-temperature Behavior of Single-Wall Carbon Nanotube Gate-all-around Field-effect Transistors, looked at how electronic devices or switches made up of nanomaterials work over a wide range of ultra-low temperatures and whether they can be appropriately utilized for such applications.
“Over the last two decades, nanomaterials have become ubiquitous in applications covering the gamut of modern life—from strengthening structures and materials used in everyday applications; cleaning agents, targeted delivery of life saving medications and cosmetic products; efficient power generation; and development of advanced and powerful electronic circuits and systems,” Nekovei said.
“This advancement has coincided with the world of electronic applications reaching interesting and challenging frontiers,” Verma said. “These include the realm of deep-space applications and quantum computing. All these future-defining applications have one thing in common—the need for the electronic systems to work over a wide range of ultra-low temperatures.
“Extreme temperatures are a routine feature of outer space. Current quantum computing technology also requires very low temperatures for these systems to work efficiently,” he added.
The device they looked at for this project is a gate-all-around field effect transistor, among the newest field-effect transistor device design being explored by the semiconductor industry. For this work, they also considered a carbon nanotube as the current carrying channel within the device and modeled its operation for various temperatures ranging from -452F to -64F, they said.
A carbon nanotube is a tube composed of carbon atoms with thickness on the scale of nanometers or about 50,000 times thinner than a human hair, Verma said.
“Our work relied on heavy utilization of the High-Performance Computing Cluster hosted at the Javelina Engineering Complex,” Verma said. “The effort involved deploying computer codes of thousands of lines developed by us to track the path of each and every electron as it moved within the device and delivered electrical power.”
They discovered that temperature has a profound, but fortunately, expected effect on the behavior of the device. “The lower the temperature, the higher the power the device delivered,” Verma said. “This is because of a known effect of lowering of electrical resistance with temperature, which causes a larger current at the same voltage.”
Most importantly, they found that such low temperatures had no harmful effects on the working of the device. “Qualitatively, the devices behaved as would be expected, whether under high-frequency gigahertz switching or under steady-state DC conditions,” he added.
Another significant aspect they explored was a conjecture proposed decades ago on the possibility of high-frequency terahertz noise in devices composed of nanomaterials such as nanotubes or nanowires, particularly at very low temperatures, under steady-state DC conditions.
“What we found was the absence of any such noise,” Nekovei said. “This potentially makes devices composed of nanomaterials working at low temperatures even more attractive for niche applications including space and quantum computing.”
These conclusions are part of ongoing research efforts by Verma and Nekovei to explore the use of nanomaterials for extreme environments. The initial foundation was laid about three years ago through a NASA Jet Propulsion Laboratory grant. Verma also is guest editing a special topics issue on Nanomaterials in Extreme Environments for the Journal Frontiers in Nanotechnology.
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