ICT2014 Abstracts

InAs nanowires, as one of high mobility semiconductors, have been grown by MOCVD and MBE method and their transport properties have been extensively investigated. The carrier mobility of InAs nanowires is dependent upon the nanowire radius. Recently, the thermoelectric properties of InAs nanowires, synthesized by catalyst-assisted CVD, have been reported that the thermopower is able to be controlled by tuning the gating voltage. We have investigated the thermoelectric properties of single InAs nanowire grown by catalyst-free MBE. The thermoelectric properties of InAs nanowire were measured with temperature (40 to 300 K) using a microfabricated thermoelectric measurement platform. Results showed that the Seebeck coefficients increased with temperature and reached approximately 200 μV/K at 300 K. The more or less linear behavior of Seebeck coefficient with temperature implied a diffusion thermopower of n-type InAs nanowire. The thermal conductivities of InAs nanowire decreased from 3.5 to 2.5 W/mK with the temperature decreasing in the range of 40 to 300 K. The electrical conductivities measured by a four-point probe method decreased from 93 to 75 S/cm with the temperature in the range of 40 to 300 K, indicating a semiconducting behavior. The transconductance of InAs nanowire was measured to estimate the field-effect mobility (approximately 1900 cm²/Vsec) and then the carrier concentration was estimated approximately 2 x 10¹⁷ /cm³. We will discuss the effects of carrier concentration and mobility on the thermoelectric transport of InAs nanowire in more detail.