About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Characterization of Minerals, Metals and Materials 2026 - In-Situ Characterization Techniques
|
| Presentation Title |
Complementary use of high-resolution scanning transmission electron microscopy and atom probe tomography for the examination of compositional fluctuation in AlGaN quantum well epitaxy |
| Author(s) |
Hung-Wei Yen, Ying-Chun Chao, Chia-Yen Huang |
| On-Site Speaker (Planned) |
Hung-Wei Yen |
| Abstract Scope |
An identical AlGaN growth process for UVC light-emitting diodes was applied to two high-quality AlN buffer layers with differing initial defect densities. The resulting AlGaN epitaxial layers were investigated using high-resolution scanning transmission electron microscopy and atom probe tomography. Geometric phase analysis of the HR-STEM data revealed that the sample grown on the more compressively strained buffer exhibited greater local lattice constant distortion within the multiple quantum well region. APT confirmed that this distortion stemmed from strain-induced gallium segregation within the MQWs. Comparative compositional analysis indicated that nanoscale compositional fluctuations promoted further Ga incorporation during epitaxy, leading to growth front destabilization and the nucleation of new defects. One-dimensional compositional profile from APT data suggested that nitrogen desorption occurred during the stress relaxation of the AlGaN layer. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Characterization, Thin Films and Interfaces, Nanotechnology |