Peidong Yang and his colleagues at Berkeley Lab have created a new type of nanostructure with enhanced thermoelectric performance: thin single-crystalline silicon membranes that have been decorated with a high density of nanoscopic holes. These "holey silicon" (HS) nanostructures exhibit good mechanical strength and reproducibly low thermal conductivity while maintaining sufficient electrical quality, making them viable candidates for thermoelectric applications.
The Berkeley Lab structures were fabricated by either nanosphere or block-copolymer lithography, both of which are scalable for practical device application. By reducing the pitch of the hexagonal holey pattern down to 55 nm with 35% porosity, the thermal conductivity of HS is consistently reduced by 2 orders of magnitude and approaches the amorphous limit. With a ZT value of ~0.4 at room temperature, the thermoelectric performance of this technology is comparable with the best value recorded in a silicon nanowire system.
STATUS: Patent pending. Available for licensing or collaborative research.
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REFERENCE NUMBER: JIB-2854