A reversible thermoelectric converter includes first and second quantum well diodes and an electrical connection between the first and second quantum well diodes without a thermal barrier between them. Each quantum well diode includes first and second electrodes wherein electrons are quantized in discrete energy levels and a dielectric layer providing a potential barrier between the first and second electrodes. When electrons in the first quantum well diode have a higher temperature than the electrons in the second quantum well diode, electric voltage fluctuations resulting from transitions of the electrons between the energy levels in the first quantum well diode are coupled from the first quantum well diode to the second quantum well diode. The reversible thermoelectric converter can be operated for power conversion of thermal energy to electric energy, as a heat pump or a refrigerator, or as an amplifier. A planar array of reversible thermoelectric converter elements provides a desired output voltage and current.