Condensed-Matter Physics & Materials Science Seminar

Thermoelectric materials have attracted considerable interest for many years because of their versatile applications such as power generation from waste heat and all-solid-state electric refrigeration. High efficiency thermoelectric devices require materials with large thermoelectric figure of merit (ZT=S2T/, where S = Seebeck coefficient, = electrical conductivity, = thermal conductivity, and T = absolute temperature). Since solid solution is an efficient way to improve ZT, there have been a number of reports on solid solution quaternary or higher component systems. However, in order to investigate the thermoelectric properties as a function of composition in these complicated systems, fabrication and measurements based on a one-composition-at-a-time approach is too time consuming. We have developed a high-throughput screening system for thermoelectric material exploration. This system consists of a combinatorial pulsed laser deposition tool based on natural spread method and a thermoelectric power factor (S2screening device which allows us to measure electric conductivity and Seebeck coefficient of over 1000 sample points within 6 hours. Using this high-throughput screening system, we can typically fabricate a ternary thermoelectric property diagram within a day. We will demonstrate the success of the design with a (Zn,Al)O binary composition-spread film on a Al2O3 (0001) substrate and a (Ca1-x-ySrxLay)3Co4O9 ternary composition-spread film on a Si(100) substrate.