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

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-ω and 1-ω 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 β-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=σS2T/k, was measured to be ∼0.12. This value is around 120 times higher than the reported maximum value of bulk β-SiC.