Revolutionary Solid-State Thermal Transistor Unveiled by UCLA

New electronic devices precisely and quickly control turning heat on and off.

A team of UCLA scientists has unveiled the first stable, fully solid-state thermal transistor of its kind that uses electric fields to control thermal movement in semiconductor devices.

Group research recently published in journals scienceLet’s take a closer look at how the device works and its potential uses. With the highest speed and performance, this transistor could break new ground in thermal management in computer chips through atomic-level design and molecular engineering. This advance could also improve our understanding of how the human body regulates heat.

A leap forward in thermal management technology

“Precise control over how heat flows through materials has long been a dream of physicists and engineers, but an elusive dream,” said co-author of the study, a professor of mechanical and aerospace engineering. Professor Yongji Hu said. University of California Los Angeles Samueli Engineering School. ” This new design principle is a major leap forward in that direction, as it manages heat transfer by switching electric fields on and off, just as has been done with electrical transistors for decades. ”

Electrical transistors are fundamental building blocks of modern information technology. These were first developed by Bell Laboratories in his 1940s and feature his three terminals: gate, source, and sink. When an electric field is applied through the gate, it controls how electricity (in the form of electrons) moves through the chip. These semiconductor devices amplify or switch electrical signals and power. However, as the size of transistors continues to shrink over the years, billions of transistors can fit onto a single chip, resulting in increased heat generated by the movement of electrons, which impacts chip performance. Masu. Traditional heat sinks passively remove heat from hot spots, but finding more dynamic controls to actively control heat has remained a challenge.

overcome previous limitations

Efforts have been made to tune thermal conductivity, but their performance has been degraded by dependence on moving parts, ion motion, or solution components. The result is heat transfer switching speeds of several minutes or much slower, leading to problems with performance reliability and incompatibility with semiconductor manufacturing.

The new thermal transistor boasts field effect (modulation of a material’s thermal conductivity by applying an external electric field) and is fully solid-state (no moving parts), offering high performance and compatibility with semiconductor integrated circuits. manufacturing process. The team’s design incorporates electric field effects on charge dynamics at atomic interfaces and achieves high performance using negligible power to continuously switch and amplify heat fluxes.

Record-breaking performance and potential applications

The UCLA team demonstrated an electrically gated thermal transistor that achieved record high performance at switching speeds of more than 1 megahertz, or 1 million cycles per second. It also offered his 1,300% tunability of thermal conductance and reliable performance of over 1 million switching cycles.

“This research is the result of an exciting collaboration that allows us to leverage our detailed understanding of molecules and interfaces to make significant advances in the control of important material properties that can have real-world implications.” researchers say. Author Paul Weiss is a professor of chemistry and biochemistry. “We were able to improve both the speed and magnitude of thermal switching effects by orders of magnitude over what was previously possible.”

The research team’s proof-of-concept design creates self-assembled molecular interfaces that act as conduits for heat transfer. Switching the electric field on and off through a third terminal gate controls the thermal resistance between the atomic interfaces, allowing heat to move precisely through the material. The researchers verified the transistor’s performance with spectroscopic experiments and performed ab initio calculations that take into account field effects on the properties of atoms and molecules.

This research demonstrates scalable innovations for sustainable energy in chip manufacturing and performance. Hu suggested that this concept also provides a new way to understand the human body’s thermal management.

“At a very fundamental level, this platform has the potential to provide insight into molecular-level mechanisms in living cells,” Hu added.

Reference: Man Li, Huan Wu, Erin M. Avery, Zihao Qin, Dominic P. Goronzy, Hu Duy Nguyen, Tianhan Liu, Paul S. Weiss, Yongjie Hu, “Electrically Gated Molecular Thermal Switch,” November 2023 2 Day, science.
DOI: 10.1126/science.abo4297

Other authors on the paper, all from UCLA, include Man Li, Huan Wu, Erin Avery, Zihao Qin, Dominic Goronzy, Huu Duy Nguyen, and Tianhan Liu. Hu and Weiss are also affiliated with the California NanoSystems Institute and UCLA Samueli’s Department of Bioengineering and Department of Materials Science and Engineering.

This research National Institutes of Health, Alfred P. Sloan Foundation, National Science Foundation. Technical support was provided by UCLA Nanolab and the California NanoSystems Institute at UCLA. Computational resources were provided by the UCLA Institute for Digital Research and Education and the Advanced Cyberinfrastructure Coordination Ecosystem: Services & Support.