Suppression of thermal conductivity in InxGa1−xN alloys by nanometer-scale disorder

Appl. Phys. Lett. 102, 121906 (2013).

T. Tong, D. Fu, A. X. Levander, W. J. Schaff, B. N. Pantha, N. Lu,B. Liu, I. Ferguson, R. Zhang, J. Y. Lin, H. X. Jiang, J. Wu, David G. Cahill.

Department of Materials Science and Engineering and Materials Research Laboratory, University of Illinois Urbana, Illinois 61801, USA and

Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA and

Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing University, Nanjing, Jiangsu 210093, People’s Republic of China and

Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA and

Department of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14853, USA and

Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409, USA and

Department of Electrical and Computer Engineering, University of North Carolina, Charlotte, North Carolina 28223, USA.

 

Abstract

 

We have systematically measured the room-temperature thermal conductivity of epitaxial layers of In_xGa_1−xN alloys with 15 different Indium compositions ranging from 0.08 to 0.98 by time-domain thermo-reflectance method. The data are compared to the estimates of the strength ofphonon scattering by cation disorder. The thermal conductivity is in good agreement with the theoretical modeling results based on the mass difference for In-rich (x > 0.9) and Ga-rich (x < 0.2) compositions. At intermediate compositions (0.2 < x < 0.9), the thermal conductivity is strongly suppressed below the values expected for homogeneous alloys. We attribute this suppression of thermal conductivity to phonon scattering by nanometer-scale compositional inhomogeneities in alloys.

© 2013 American Institute of Physics

 

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