I will report on our ongoing program to demonstrate a thermal-to-electric power conversion near Carnot efficiency, using semiconductor, heterostructure nanowires . This experimental project has its roots in earlier work on quantum ratchets , which under certain circumstances can be operated as heat engines . The energy selectivity afforded by low-dimensional systems allows it, in principle, to tailor the energy spectrum of electrons participating in thermoelectric flow for either optimal efficiency (Carnot) or optimal power conversion (at much lower efficiency).

This research will be presented within a larger context of experimental work on ratchet systems, including a report on heat-activated motion of millimeter-sized Leidenfrost droplets on hot, ratchet-shaped metal surfaces which may have applications in heat-activated liquid cooling systems.