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You are here: Home / Publications / New Publication! Thermal conductivity of rutile germanium dioxide

New Publication! Thermal conductivity of rutile germanium dioxide

September 17, 2020 By Peter Meisenheimer

Abstract: Power electronics seek to improve power conversion of devices by utilizing materials with a wide bandgap, high carrier mobility, and high thermal conductivity. Due to its wide bandgap of 4.5 eV, β-Ga2O3 has received much attention for high-voltage electronic device research. However, it suffers from inefficient thermal conduction that originates from its low-symmetry crystal structure. Rutile germanium oxide (r-GeO2) has been identified as an alternative ultra-wide-bandgap (4.68 eV) semiconductor with a predicted high electron mobility and ambipolar dopability; however, its thermal conductivity is unknown. Here, we characterize the thermal conductivity of r-GeO2 as a function of temperature by first-principles calculations, experimental synthesis, and thermal characterization. The calculations predict an anisotropic phonon-limited thermal conductivity for r-GeO2 of 37 W m−1 K−1 along the a direction and 58 W m−1 K−1 along the c direction at 300 K where the phonon-limited thermal conductivity predominantly occurs via the acoustic modes. Experimentally, we measured a value of 51 W m−1 K−1 at 300 K for hot-pressed, polycrystalline r-GeO2 pellets. The measured value is close to our directionally averaged theoretical value, and the temperature dependence of ∼1/T is also consistent with our theory prediction, indicating that thermal transport in our r-GeO2 samples at room temperature and above is governed by phonon scattering. Our results reveal that high-symmetry UWBG materials, such as r-GeO2, may be the key to efficient power electronics.

Full text available from Applied Physics Letters

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  • New Publication! Multiferroic heterostructures for spintronics January 4, 2021
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  • New Publication! Thermal conductivity of rutile germanium dioxide September 17, 2020

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Our work is multidisciplinary. We employ concepts and tools from the fields of materials science, chemistry, physics and electrical engineering to develop new methods to investigate and engineer … Read More

News

New Publication! Multiferroic heterostructures for spintronics

January 4, 2021 By Peter Meisenheimer

New Publication! Property and cation valence engineering in entropy-stabilized oxide thin films

October 19, 2020 By Peter Meisenheimer

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