High-Power Thermoelectric Generator Needs Thermal Difference of Only 5ºc

To address these problems, a team of Japanese researchers from Waseda University, Osaka University, and Shizuoka University designed and successfully developed a novel silicon-nanowire thermoelectric generator, which experimentally demonstrated a high power density of 12 microwatts per 1cm2, enough to drive sensors or realize intermittent wireless communication, at a small thermal difference of only 5ºC.

“Because our generator uses the same technology to manufacture semiconductor integrated circuits, its processing cost could be largely cut through mass production,” says Professor Takanobu Watanabe of Waseda University, the leading researcher of this study. “Also, it could open up a pathway to various, autonomously-driven IoT devices utilizing environmental and body heats. For instance, it may be possible to charge your smartwatch during your morning jog someday.”

The newly developed thermoelectric generator lost the cavity structure but instead shortened the silicon nanowires to 0.25 nanometers, since simulations showed that the thermoelectric performance improved by minimizing the device. Professor Watanabe explains that despite its new structure, the new thermoelectric generator demonstrated the same power density as the conventional devices. More surprisingly, thermal resistance was suppressed, and the power density multiplied by ten times by thinning the generator’s silicon substrate from the conventional 750 nanometers to 50 nanometers with backside grinding.

Though the research team will need to improve the quality of the generator for stationary power generation in various conditions, Professor Watanabe hopes that the results achieved in this study will serve to support power technology in the IoT-based society.

This study was presented at the 2018 Symposia on VLSI Technology and Circuits held in Hawaii, USA on June 18-22, 2018.

Contacts and sources:
Jasper Lam
Waseda University

Citation:  10μW/cm2-Class High Power Density Silicon Thermoelectric Energy Harvester Compatible with CMOS-VLSI Technology
Presented at the 2018 Symposia on VLSI Technology and Circuits at 5:30 a.m. on June 21 (Thurs), 2018 (Japan Standard Time)
Corresponding author: Motohiro Tomita, Junior Researcher at Waseda University