Abstract
Enhancement of the dimensionless thermoelectric figure of merit ZT is predicted theoretically in nanowires. In our study, we developed bismuth nanowires encapsulated in quartz templates. Bismuth nanowires were fabricated by injecting molten bismuth into a nano-scale hole of the quartz template and then recrystallized by cooling the temperature gradually. From 50-nm to 1-μm-diameter bismuth nanowires were successfully obtained by utilizing this fabrication technique. The measurement of the Seebeck coefficient and the electrical resistivity in the same nanowire sample is the first in the world. Differences between the thermoelectric properties of nanowires and bulk were observed in detail. A decrease of the carrier mobility was predicted by analyzing these thermoelectric properties with theoretical calculation considering the mean free path limitation. Therefore, new electrodes fabrication procedure for measurements of the Hall coefficient and the four-wire resistance of bismuth wires was established utilizing focused-ion-beam processing in order to evaluate the carrier mobility.
