A Novel Three-Dimensional Thin-film Thermoelectric Generator for Wearable Applications
Mehmet C. Ozturk
Project runs from 08/01/2017 to 07/31/2020
An integrated research, education, and outreach program is proposed that will introduce a novel, highly efficient, photo-enhanced thermoelectric generator. The new device, which has the potential to transform the thermoelectric industry will provide > 100X improvement in output voltage compared to conventional devices. The new device achieves this performance enhancement thanks to an entirely new device architecture, which significantly reduces the parasitic losses as well as its ability to harvest both photoexcited (light) and thermoelectric (heat) carriers. The program has four main goals:
1. Device Demonstration: A CMOS compatible, wafer-scale micro-fabrication process will be developed to fabricate a highly efficient, photo-enhanced thermoelectric energy generator (PTEG) on inexpensive silicon wafers. The fabrication will rely on mature processes and techniques used in micro-electro-mechanical-systems (MEMS) integration.
2. Material Development: The work will focus on improving the material properties for room-temperature applications. A particular composition of Si(1-x)Ge(x) providing high degeneracy of the band minima (N=10) is proposed. Nanostructuring and partial amorphization of the semiconductor material will be used to further improve the figure-of-merit ZT using a novel microwave method previously introduced by the principal investigator.
3. Modeling: A comprehensive system model will be developed to optimize the device architecture. The effort will include both thermal and semiconductor modeling, which will focus on carrier transport, photoexcitation, and ambipolar diffusion.
4. A broad education plan will be developed including a new teaching initiative in the upper-division undergraduate curriculum, involvement of undergraduates in research, and outreach, with aims to introduce energy conversion materials to the general public.
The proposed photo-enhanced thermoelectric generator has the potential to revolutionize the way the thermoelectric modules are manufactured. While this proposal focuses on energy harvesting, innovations introduced to the device architecture are also applicable to thermoelectric devices intended for cooling or infrared imaging applications. The specific material and device configuration used in this proposal has a broad range of indoor applications ranging from wearable electronics for monitoring of human health and environmental conditions to commercial systems that require self-powered, continuous and wireless monitoring. The proposed device architecture is compatible with modern thin film thermoelectric materials and manufacturing processes.
We anticipate that this research should lead to (a) discovery of new ways to harvest both light and heat energy, and (b) a competitive silicon-compatible thermoelectric material for room temperature applications. The device is particularly efficient for use with complex systems that involve sensors and electronics. Hence, it will potentially have high commercial market acceptance in emerging, self-powered, connected sensor systems. This program is a natural extension of a highly fertile line of leading research by the PIs, which has generated many publications in top ranked journals, and has been featured in both wide and specialized audience journals (Science, Nature, PRL, etc.).