Electrodeposition and characterization of nano-crystalline antimony telluride thin films |
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Authors: | J.L. Lensch-FalkD. Banga P.E. Hopkins D.B. RobinsonV. Stavila P.A. SharmaD.L. Medlin |
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Affiliation: | a Sandia National Laboratories, Livermore, CA 94550, USAb Sandia National Laboratories, Albuquerque, NM 87185, USAc Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA 22904, USA |
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Abstract: | Electrodeposition is a promising low-cost method to fabricate nanostructured thermoelectric thin films such as Sb2Te3. However, electrodeposition of crystalline Sb2Te3 without the need for additional processing and with good compositional control has presented a challenge. Here we report on the electrodeposition of crystalline Sb2Te3 thin films at room temperature from a tartaric-nitric acid electrolyte using a pulsed, potentiostatic process. The effects of synthesis conditions on the resulting microstructure and compositional homogeneity are investigated using x-ray diffraction, electron diffraction, electron microscopy, and energy dispersive x-ray spectroscopy. The composition of the Sb-Te films was found to be dependent on the interval between pulses, a result that is likely due to the slow kinetics associated with Sb2Te3 formation at the surface. We also observed a change in texture and microstructure with varied applied pulse duration: for short pulse durations a lamellar microstructure with a {000?} texture forms, whereas for longer pulse durations a more equiaxed and randomly oriented microstructure forms. The thermal conductivities of the pulsed electrodeposited films are surprisingly low at less than 2 W/K·m and are found to systematically decrease with reduced pulse time. |
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Keywords: | Thermoelectrics Electrochemical deposition Transmission electron microscopy Microstructure Thermal conductivity |
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