| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2018) | |
| Thin Films | Thursday Sessions |
| Session TF-ThM |
| Session: | Nanostructured Surfaces and Thin Films: Synthesis and Characterization III |
| Presenter: | John Gaskins, University of Virginia |
| Authors: | J. Gaskins, University of Virginia G. Kotsonis, Pennsylvania State University A. Giri, University of Virginia S. Ju, University of Tokyo, Japan A. Rohskopf, Massachusetts Institute of Technology Y. Wang, University of California, Los Angeles T. Bai, University of California, Los Angeles E. Sachet, North Carolina State University C. Shelton, North Carolina State University Z. Liu, University of Notre Dame Z. Cheng, Georgia Institute of Technology B. Foley, Pennsylvania State University S. Graham, Georgia Institute of Technology T. Luo, University of Notre Dame A. Henry, Massachusetts Institute of Technology M. Goorsky, University of California, Los Angeles J. Shiomi, University of Tokyo, Japan J.-P. Maria, Pennsylvania State University P. Hopkins, University of Virginia |
| Correspondent: | Click to Email |
We present experimental measurements of the thermal boundary conductance (TBC) from 77 − 500 K across isolated heteroepitaxially grown ZnO films on GaN substrates. This data provides an assessment of the underlying assumptions driving phonon gas based models, such as the diffuse mismatch model (DMM), and atomistic Green’s function (AGF) formalisms used to predict TBC. Our measurements, when compared to previous experimental data, suggest that TBC can be influenced by long wavelength, zone center modes in a material on one side of the interface as opposed to the “vibrational mismatch” concept assumed in the DMM; this disagreement is pronounced at high temperatures. At room temperature, we measure the ZnO/GaN TBC as 490[+150, −110] MW m−2 K−1. The disagreement among the DMM and A GF, and the experimental data at these elevated temperatures, suggests a non-negligible contribution from other types of modes that are not accounted for in the fundamental assumptions of these harmonic based formalisms, which may rely on anharmonicity . Given the high quality of these ZnO/GaN interfaces, these results provide an invaluable, critical, and quantitative assessment of the accuracy of assumptions in the current state of the art computational approaches used to predict phonon TBC across interfaces.