M44.00007. First-principles study of enhanced thermal conductivity in ordered AlGaO3 alloys

Presented by: Sai Mu


Abstract

Monoclinic gallium oxide (Ga2O3) has promising applications in high-power and high-frequency electronics due to its wide band gap. However, practical device applications are hampered by its low thermal conductivity. To improve the thermal properties of Ga2O3 devices, we propose to alloy Ga2O3 with Al2O3, forming a low-energy ordered structure at the 50% concentration [1]. We investigate the lattice thermal conductivity of monoclinic Ga2O3 and of the ordered AlGaO3 alloy using the phonon Boltzmann transport equation, with the harmonic and third-order anharmonic force constants calculated from density functional theory. We find that the thermal conductivity of AlGaO3 is raised by more than 70% compared to Ga2O3. The enhancement is ascribed to (1) increased group velocities and (2) reduced anharmonic scattering rates due to the reduced weighted phase space. The findings offer an avenue towards improved heat dissipation from Ga2O3 devices. The work was supported by the GAME MURI of the Air Force Office of Scientific Research.

Authors

  • Sai Mu
  • Hartwin Peelaers
  • Chris Van de Walle


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