Misorientation dependence of Al2O3 grain boundary thermal resistance

The room-temperature thermal resistance of model low-angle (0001) twist bicrystal Al2O3 grain boundaries was measured as a function of misorientation angle using the 3 omega thermal conductivity testing technique. The work yields interfacial thermal resistances of 0.44 x 10(-8), 1.2 x 10(-8), and 1.54 x 10(-8) Km(2) W-1 for the similar to 1.3 degrees, similar to 8.0 degrees, and similar to 13 degrees twist grain boundaries, respectively. The interfacial thermal resistance correlates with the grain boundary energy calculated from the Read-Shockley model. The results indicate significant anisotropy in the Kapitza resistance whose magnitude is dominated by local structural defects at the grain boundary rather than spectral mismatch between grains. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4788688]