Electric field effect on thermopower in cylindrical microwires

The electric field effect (EFE) in a coaxial cylindrical capacitor configuration was used to study the modification of transport and thermoelectric properties of the semiconductors PbTe and Bi₂Te₃ as glass coated microwires. Theoretical analysis of microwire EFE was done on the basis of Poisson equation in cylindrical geometry with corresponding boundary conditions. The radial dependences of transport characteristics have been calculated for PbTe and Bi₂Te₃ wires at positive and negative polarity of the gate voltage under the assumption that the carrier mobility is similar with the bulk material mobility. Some aspects of microwire fabrication by different methods as well as some general wire characteristics are presented. The first results of experimental measurements of wire transport properties under EFE show the increasing or decreasing of the average Seebeck coefficient in dependence of gate potential polarity in accordance with the theoretical analysis.