Seebeck effect in a nanometer-scale dot in a Si nanowire observed with electron counting statistics

We performed electron counting statistics to measure the thermoelectric effect in a nanometer-scale silicon dot. To separate the 100-nm-long dot from a silicon nanowire, we used an electrostatically created 30-nm-long energy barrier. By measuring current through a nearby sensor, we observed the random motion of single electrons between the dot and silicon nanowire. The statistics of single-electron motion provides us with information on temperature and voltage at the dot. Under the detailed balance assumption, we determined the temperature difference and the Seebeck voltage between the dot and silicon nanowire. The validity of our analysis was confirmed by observing the energy-barrier height dependence of the Seebeck coefficient. Furthermore, by counting the electrons leaving the dot, a minute output power on the order of sub-zeptowatt from the dot to the silicon nanowire was estimated.