Atomic-scale visualization of defect-induced localized vibrations in GaN

作者：Hailing Jiang, Tao Wang, Zhenyu Zhang, Fang Liu, Ruochen Shi, Bowen Sheng, Shanshan Sheng, Weikun Ge, Ping Wang, Bo Shen, Bo Sun, Peng Gao, Lucas Lindsay, Xinqiang Wang · 发表于：Nature Communications · 年份：2024 · DOI：10.1038/s41467-024-53394-z · 被引用次数：19 · 研究领域：Thermal properties of materials、GaN-based semiconductor devices and materials、Semiconductor materials and devices

Phonon engineering is crucial for thermal management in GaN-based power devices, where phonon-defect interactions limit performance. However, detecting nanoscale phonon transport constrained by III-nitride defects is challenging due to limited spatial resolution. Here, we used advanced scanning transmission electron microscopy and electron energy loss spectroscopy to examine vibrational modes in a prismatic stacking fault in GaN. By comparing experimental results with ab initio calculations, we identified three types of defect-derived modes: localized defect modes, a confined bulk mode, and a fully extended mode. Additionally, the PSF exhibits a smaller phonon energy gap and lower acoustic sound speeds than defect-free GaN, suggesting reduced thermal conductivity. Our study elucidates the vibrational behavior of a GaN defect via advanced characterization methods and highlights properties that may affect thermal behavior. Authors identify three types of defect-derived phonon modes in GaN, including localized defect modes, a confined bulk mode, and a fully extended mode. The defects exhibit a smaller phonon energy gap and lower sound speeds, indicating reduced thermal conductivity.