Experimental Realization of a Quantum Dot Energy Harvester.

We demonstrate experimentally an autonomous nanoscale energy harvester that utilizes the physics of resonant tunneling quantum dots. Gate-defined quantum dots on GaAs/AlGaAs high-electron-mobility transistors are placed on either side of a hot-electron reservoir. The discrete energy levels of the quantum dots are tuned to be aligned with low energy electrons on one side and high energy electrons on the other side of the hot reservoir. The quantum dots thus act as energy filters and allow for the conversion of heat from the cavity into electrical power. Our energy harvester, measured at an estimated base temperature of 75 mK in a He3/He4 dilution refrigerator, can generate a thermal power of 0.13 fW for a temperature difference across each dot of about 67 mK.This work was funded by EPSRC(UK). G. J. acknowledges financial support from China Scholarship Council and GBCET. R. S. acknowledges financial support from the Spanish MINECO via Grant No. FIS2015-74472-JIN (AEI/FEDER/UE), the Ramón y Cajal program RYC-2016-20778 and through the “María de Maeztu” Programme for Units of Excellence in R&D (MDM-2014-0377). Work by A. N. J. was supported by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES) under Award No. DE-SC0017890. B. S. acknowledges financial support from the Ministry of Innovation NRW via the “Programm zur Förderung der Rückkehr des hochqualifizierten Forschungsnachwuchses aus dem Ausland.” This research was supported in part by the National Science Foundation under Grant No. NSF PHY-1748958