Reduced Thermal Conductivity in Er-doped Epitaxial InxGa1-xSb Alloys
J. P. Feser*, D. Xu*, H. Lu, Y. Zhao, A. Shakouri, A. C. Gossard, and A. Majumdar, Appl. Phys. Lett. 103, Art. No. 103102 (2013).
The thermal conductivity of epitaxially grown semiconducting alloys of InxGa1‑xSb is studied and compared to Er doped alloys. At concentrations as low as ~0.4% vol. Er, the Er coalesces to form epitaxially embedded ErSb nanocrystals which reduce the thermal conductivity compared to undoped alloys. The thermomechanical properties of epitaxial ErSb are studied for comparison. ErSb is found to be metallic with significantly higher thermal conductivity and stiffness than InxGa1‑xSb alloys. The stiffness and density contrast from ErSb nanocrystals helps explain its high effectiveness as a phonon scattering center, as they are the highest of any known lattice matched material pair.