The size-dependent thermoelectric response of tungsten-constantan thermocouple in the sub-micro scale

We present the behavior of the thermoelectric response in a nanoscale tungsten-constantan (Cu 58%, Ni 42%) thermocouple (TC). The TC is tip-section typed and fabricated by the stepping method. The thermal electromotive force (emf) showed nearly linear behavior versus temperature over the range from 0 to 100 ∘ C. For the thermocouples with contact radius below 300 nm, the Seebeck coefficient decreased with the size of thermocouples turning smaller. According to the theory based on the free-electron model, the size-dependence thermal electric response may be ascribed to the change of electronic property in nanoscale.