Highly enhanced thermoelectric figure of merit of a beta-SiC nanowire with a nanoelectromechanical measurement approach

초록

We developed a reliable and highly reproducible way of fabricating a one-stop measurement platform for characterizing the thermoelectric properties of individual nanowires (NWs) using a focused ion beam and a nanomanipulator. 3-omega and 1-omega signals obtained by the four-point-probe method were used in measuring the thermal and electrical conductivities of the NW. Subsequently, the Seebeck coefficient was measured by using additional nanoelectrodes including a nanoheater. The thermal conductivity of the single beta-SiC NW was obtained at 86.5 +/- 3.5 W/mK. The Seebeck coefficient was obtained to be -1.21 mV/K by using the same measurement platform. Thus, the dimensionless figure of merit, ZT = sigma(ST)-T-2/k, was measured to be similar to 0.12. This value is around 120 times higher than the reported maximum value of bulk beta-SiC.

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