Radial electric field effect on thermoelectric transport properties of Bi_2Te_3 cylindrical nanowire coaxial structure

摘要

Radial electric field effect (REFE) on the thermoelectric figure of merit and Seebeck coefficient S are studied for a coaxial cylindrical capacitor configuration on the basis of bipolar intrinsic semiconductors. Theoretical analysis of REFE nanowire was done based on Poisson's equation in cylindrical geometry with corresponding boundary conditions. Using Newton's method the radial variation of the local Seebeck coefficient, carrier concentration and others transport characteristics are calculated for the bipolar Bi_2Te_3 nanowires neglecting size quantization. The dependence of the thermoelectric parameters on the gate voltage is studied. It is shown that the existence of the transition bipolar-monopolar semiconductor, electric field, differences in carrier masses and mobility essentially affect the thermoelectric properties. The thermoelectric figure of merit can be significantly increased by REFE.