| AVS 57th International Symposium & Exhibition | |
| Advanced Surface Engineering | Tuesday Sessions |
| Session SE-TuA |
| Session: | Surface Engineering for Thermal Management |
| Presenter: | J.J. Gengler, Air Force Research Laboratory |
| Authors: | J.J. Gengler, Air Force Research Laboratory A.A. Voevodin, Air Force Research Laboratory D. Music, RWTH Aachen University, Germany F.H.-U. Basse, RWTH Aachen University, Germany J.M. Schneider, RWTH Aachen University, Germany |
| Correspondent: | Click to Email |
Thermal conductivity trends in RuOx thin films of varying stoichiometry were characterized with a time-domain thermoreflectance (TDTR) technique. At an O/Ru ratio of x = 1.69, a faceted film surface is observed with a measured thermal conductivity value of 28.8 ± 0.8 W m-1 K-1. With an O/Ru ratio of x = 2.24, nanorod formation occurs. These films were grown by a reactive magnetron sputtering technique with nonrotating substrates oriented 200 normal to the Ru target. Such material synthesis conditions resulted in a gradient sample structure at the onset of nanorod formation. As a result, the RuO2.24 samples exhibited gradually changing surface roughness (rms of 12 nm – 200 nm) and thermal conductivity values (22 W m-1 K-1 – 5 W m-1 K-1), respectively. The thermal conductivity of the thin film samples studied here are all well below that of single crystal RuO2 with tetragonal rutile structure (50 W m-1 K-1 [1]). The samples also have an inverse relationship of thermal conductivity with Seebeck coefficient [2], which is desirable for improving the figure of merit for thermoelectric performance.
References
[1] Ferizovic D, Hussey LK, Huang Y-S, Munoz M. Determination of the room temperature thermal conductivity of RuO2 by the photothermal deflection technique. Appl Phys Lett 2009;94:131913.
[2] Music D, Basse F H-U, Habdorf R, Schneider JM. Synthesis and thermoelectric properties of RuO2 nanorods. J Appl Phys, submitted for review.