Dresden 2017 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 28: Focussed Session: Oxide Semiconductors for Novel Devices I
DS 28.5: Vortrag
Mittwoch, 22. März 2017, 10:45–11:00, CHE 89
Anisotropic thermal conductivity in Ga2O3 — •Mitdank Rüdiger1, Handwerg Martin1,3, Galazka Zbigniew2, and Fischer Saskia F.1 — 1AG Novel Materials, Institut für Physik der Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin, Germany — 2Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2 , 12489 Berlin, Germany — 3Helmholtz-Zentrum Berlin für Materialien und Energie, 14109 Berlin, Germany
The monoclinic crystal structure of β-Ga2O3 causes a significant anisotropy of the thermal properties. The temperature-dependent values of the thermal diffusivity D in [010] and [001] direction as well as thermal conductivity values λ in [100], [010] and [001] direction using Mg-doped insulating monoclinic β-Ga2O3 bulk crystals were measured by the 2-Omega-method [1,2]. The measurements were carried out by using the same sample. The room temperature values for the thermal conductivity in the main crystal axes are determined to λ[100] = 11+-1 W/(mK), λ[010] = 29+-2 W/(mK) and λ[001] = 21+-2 W/(mK). For the diffusivity we found D[100] = 3,7+-0,4 mm*/s, D[010] = 9,6+-0,5 mm*/s and D[001] = 7,1+-0,4 mm*/s. The anisotropy factor is the same and independent of temperature. We found D[010]/D[001] = λ[010]/λ[001] = 1,4+-1. The temperature dependence of the thermal diffusivity and conductivity is in accord with phonon-phonon-Umklapp-scattering for T > 150 K.
[1] Handwerg et al., SST 31, 125006 (2016) [2] A. T. Ramu and J. E. Bowers, Rev. Sci. Instr. 83 ,124903 (2012)