April AMP_Digital

simultaneously co-sputtering Ni, Co, Ti, and Sb targets. Crystallization of the depos- ited alloys was promoted by in situ annealing up to 450 o C. Microstructure and thermo- electric transport properties of the films were then charac- terized. High-throughput syn- thesis and characterization generated materials genom- ic data that can be used for modeling and design. EXPERIMENTAL RESULTS As-synthesized filmcom- positions measured using Ruth- erfordbackscattering (RBS) and x-ray fluorescence (XRF) were within ±1 at.% of the target compositions. X-ray diffrac- tion (XRD) confirmed that the films were deposited as amorphous material and for- med the half-Heusler crystal structure after annealing. A clear correlation exists betweencompositionandelec- trical properties in this sys- tem (Fig. 3). Such tunability is of par- amount importance for the design of thermoelectric materials. In this case, electrical resistivity increased with in- creasing cobalt. More importantly, the Seebeck coefficient (i.e., voltage gen- erated when the system is exposed to a temperature gradient) depends strong- ly on the Co/Ni ratio, demonstrating the capability of controlling this effect by composition. The interdependence of compu- tational modeling with advanced high throughput experimentation paves the way for future materials development in this field. ~AM&P Note: This article was authored by Mark Clark of Intermolecular along with con- tributing authors Cesar Clavero of In- termolecular and Jeff Doak of QuesTek Innovations LLC. For more information: Mark Clark, senior director, Intermolecular, 3011 N. 1st St., San Jose, CA, 95134, 408.582. 5638, mark.clark@intermolecular.com. Fig. 2 — Process flow for data generation, screening validation, and characterization. Fig. 3 — Effect of composition on physical properties. Natively formed surface oxide increased by 0.5 nm, but thin filmphysical properties remained constant with time (confirmed by measurements).