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Bibliographic Details
Main Authors: Rahaman, Imteaz, Liao, Michael E., Wang, Ziqi, Kwon, Eugene Y., Sun, Rui, Li, Botong, Ellis, Hunter D., Duersch, Bobby G., Sun, Dali, Liu, Jun, Goorsky, Mark S., Scarpulla, Michael A., Fu, Kai
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2510.27228
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Table of Contents:
  • Rutile germanium dioxide (r-GeO2) has recently emerged as a promising ultrawide-bandgap (UWBG) semiconductor owing to its wide bandgap (~4.4-5.1 eV), ambipolar doping potential, and high theoretical thermal conductivity. However, experimental data on the thermal conductivity of r-GeO2 epitaxial layers have not been reported, primarily due to challenges in phase control and surface roughness. Here, we report a high thermal conductivity of 52.9 +/- 6.6 W m^-1 K^-1 for high-quality (002) r-GeO2 films grown by metal-organic chemical vapor deposition (MOCVD) and characterized using time-domain thermoreflectance (TDTR). The phase control was achieved through a seed-driven stepwise crystallization (SDSC) approach, and the surface roughness was significantly reduced from 76 nm to 16 nm (locally as low as 1 A) via chemical mechanical polishing (CMP). These results highlight the promise of r-GeO2 as a UWBG oxide platform for power electronics applications.