Reduction of Parasitic Losses to Improve Quantum Well Efficiency

78825S The recovery of waste heat from exit gases can significantly increase the energy efficiency of industrial processes. Thermoelectric devices that match the waste gas thermal resistance can dramatically increase the efficiency of industrial and automotive waste heat recovery processes. A significant improvement in the substrate on which breakthrough quantum well thermoelectric films are grown is needed to obtain the benefit of the highest measured thermoelectric materials efficiency. This project will develop new substrate materials, deposit quantum well films, and fabricate new quantum well devices for a waste heat recovery application. The fraction of heat lost through the substrate will be minimized by using a new ultra thin substrate (i.e., <5 microns) and/or using very low thermal conductivity materials (i.e., SiGe or Kapton) that have 3 to 100 times lower conductivity than pure Si. Phase I will: (1) search and identify from the literature and industry those ultra-thin and low thermal conductivity materials that are potential candidate substrate materials for use with quantum well materials; (2) fabricate some ultra-thin and low thermal conducitvity films, and evalute their properties; and (3) deposit quantum well materials on candidate substrates, measure electrical/thermal properties and determine the potential technical/economic benefit. Commercial Applications and Other Benefits as described by the awardee: The new technology should provide for economical electrical energy generation in numerous industrial waste heat recovery applications including flue and stack gases, vent gases, and combustion gases at a variety of temperatures at large-scale industrial plants (chemical plants, geothermal plants, pertroleum refineries, biorefineries, pulp and paper mils, etc.) and automobile applications where electrical energy can be extracted in vehicles from the exhaust or coolant loop.