Research Bits: November 14

Solid-state thermal transistor for heat management

Researchers from University of California Los Angeles created a stable and fully solid-state thermal transistor that uses an electric field to control a semiconductor device’s heat movement. It is compatible with integrated circuits in semiconductor manufacturing processes. The team’s design incorporates the field effect on charge dynamics at an atomic interface to allow high performance using a negligible power to switch and amplify a heat flux continuously.

In the team’s proof-of-concept design, a self-assembled molecular interface is fabricated and acts as a conduit for heat movement. Switching an electrical field on and off through a third-terminal gate controls the thermal resistance across the atomic interfaces and thereby allowing heat to move through the material with precision. The electrically gated thermal transistors achieved switching speed of more than 1 megahertz. They also offered a 1,300% tunability in thermal conductance and reliable performance for more than 1 million switching cycles. [1]

Protecting EVs from chip noise

Researchers from the University of Texas at Dallas developed sensors and on-chip countermeasures to detect and reduce noise from electromagnetic interference (EMI) in electric vehicles. “In order to convert the energy from the battery to power the systems, you need hundreds of power circuits. Each of them is going to generate a lot of noise,” said Dongsheng Brian Ma, professor of electrical engineering at UT Dallas. ” Our device detects the precursors to EMI in certain signature parameters.”

The technology works by sensing conditions such as input voltage and load current that can indicate increased EMI in power circuits. In response, the technology applies on-chip countermeasures to bring EMI back under control. The researchers note the approach could also be applied to other electronics. [2]

Transparent p-type conductors

Researchers from the University of Twente and Eindhoven University of Technology improved transparent p-type conductors by doping copper iodide (CuI) with a small amount of sulfur. The doping increased the material’s conductivity by more than five times while letting over 75% of the visible light pass through it.

While studying the sulfur-doped CuI, the researchers found dual functionality of sulfur: it acts as a catalyst in promoting copper vacancies and the high distribution of sulfur in grain boundaries leads to mixed phases in the material. Both make the material better at conducting electricity, bringing it closer to the conductivity of n-type transparent conductors for creation of fully transparent electronics such as transparent displays, solar cells, and thermoelectrics. [3]

References

1. Man Li et al., Electrically gated molecular thermal switch. Science 382, 585-589 (2023). https://doi.org/10.1126/science.abo4297
2. L. Du, D. Yan and D. B. Ma, “On-Chip Condition-Adaptive EMI Control for Switching Power ICs,” IEEE Journal of Solid-State Circuits. https://dx.doi.org/10.1109/JSSC.2023.3296560
3. Adeem Saeed Mirza et al., The role of sulfur in sulfur-doped copper(I) iodide p-type transparent conductors, Matter (2023). https://dx.doi.org/10.1016/j.matt.2023.10.003