Browsing by Author "Saito, Noboru"

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Graphene-Au nanoparticle based vertical heterostructures: A novel route towards high-ZT Thermoelectric devices
(2017-08-01)
Juang, Zhen-Yu
;
Tseng, Chien-Chih
;
Shi, Yumeng
;
Hsieh, Wen-Pin
;
Ryuzaki, Sou
Monolayer graphene exhibits impressive in-plane thermal conductivity (> 1000 W m(-1) K-1). However, the out-of-plane thermal transport is limited due to the weak van der Waals interaction, indicating the possibility of constructing a vertical thermoelectric (TE) device. Here, we propose a cross-plane TE device based on the vertical heterostructures of few-layer graphene and gold nanoparticles (AuNPs) on Si substrates, where the incorporation of AuNPs further inhibits the phonon transport and enhances the electrical conductivity along vertical direction. A measurable Seebeck voltage is produced vertically between top graphene and bottom Si when the device is put on a hot surface and the figure of merit ZT is estimated as 1 at room temperature from the transient Harman method. The polarity of the output voltage is determined by the carrier polarity of the substrate. The device concept is also applicable to a flexible and transparent substrate as demonstrated.