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▼ [19p-PA8-10] Thermoelectric Properties of Bimetal-catalyzed InGaO3(ZnO)4 Nanowire
Keywords:IGZO nanowire, thermoelectric, IGZO
Single crystalline InGaO3(ZnO)m NWs (IGZO NWs) are potentially promising thermoelectric (TE) materials since they possess natural superlattice structures, combining the inherent quantum confinement effects of a nanowire and the increased interface phonon scattering of a superlattice oxide thin film into a single TE material. However, very little attention has been given not only to the TE properties of IGZO NWs, but even to their mere fabrication. We have previously reported an efficient, low temperature InGaO3(ZnO)4 NW fabrication technique using a Mo/Au-catalyzed growth from amorphous thin film [1]. In this present study, the TE properties of a single IGZO NW grown via the bimetal-catalyst technique is reported. In order to measure the Sebeck coefficient (S) and electrical conductivity (σ), Pt/Ti electrodes were deposited onto a single NW via standard photolithographic techniques. A self-assembled thermal analysis system employing an infrared microscope as the thermometer, a nanovoltmeter as the heat source and a probe station connected to an SP analyzer to measure the TE properties. Shown in Fig. 1a is a TEM image of the as-synthesized IGZO NW, with its corresponding SAED pattern revealing perfect single crystallinity. Shown as inset in Fig. 1b is the single NW device. Its corresponding I-V curves under varying applied heater voltages reveal perfectly ohmic behaviors within -0.3 to 0.3 mV, wherein their logarithmic plots are shown in Fig. 1b. The leftward shift with increasing heater voltage is typical for an n-type semiconductor. The σ of the NW sample at 298 K is 178 mS/cm. The S is -398 µV/K, which was calculated when the slope of ΔV vs ΔT was taken. The resulting power factor is then 0.0028 mW/mK-2. These bimetal-catalyzed IGZO NWs could pave the way to efficient, transparent TE devices.