Modeling of transient thermoelectric transport in Harman method for films and nanowires

摘要: Abstract Harman method is a technique with great potential for rapidly scanning the figure-of-merit (zT) of emerging nanostructured thermoelectric materials. In AC variant this zT determined from ratio electrical resistance measured across material subjected to sinusoidal current at high and low frequencies. The frequency incorporates both ohmic Peltier responses, while frequencies component vanishes. This work employs finite element modeling transient transport equations in thin films nanowires determine regime measurable temperature voltage response an applied alternating current. lower bound requirement was found depend on nanostructures' geometry (i.e. film thickness or nanowire diameter) thermal properties. It shown that reducing diameter increases regime, often imposing challenging conditions measurement zT. Although heat losses sample surface due natural convection have little effect zT, contact between electrodes can be source large errors. These aspects should taken into account when performing experiments characterize using method.