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S5. III-N Heterostructure Characterization
S5. III-N Heterostructure Characterization
Monday,
Nov. 10, 2025 15:30-17:00
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| Presider: |
Prof. Ming-Chi Mitch Chou (National Cheng Kung University, Taiwan)
Dr. Michał Boćkowski (Institute of High-Pressure Physics, Polish Academy of Sciences, Poland) |
| Room: |
2nd Lecture Room |
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15:30 - 16:00
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Manuscript ID. 0008
Paper No. 2025-Mon-S0509-I001
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Invited Speaker:
Frank Bertram
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Advanced Nanoscale Characterization of Nitride-Based Heterostructures
Frank Bertram, Gordon Schmidt, Juergen, University of Magdeburg
We will present nano-scale correlation of structural, electronic and optical properties of nitride-based heterostructures using cathodoluminescence and electron-beam induced current directly performed in a scanning transmission electron microscope. Typical results exhibiting the complex nano-transport of excess carriers, in particular charge carriers and/or excitons, due to a specific heterostructure design of a device will be presented.
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16:00 - 16:15
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Manuscript ID. 0062
Paper No. 2025-Mon-S0509-O001
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| Bernard Gil
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Influence of 2D carrier localization on light emission in (Al,Ga)N alloys emitting in the Deep UV range.
Alexandra Ibanez, Bernard Gil, Guillaume Cassabois, Pierre Valvin, Wilfried Desrat, UMR 5221, Laboratoire Charles Coulomb and Université Montpellier 2, Montpellier, 34095,France; Nikita Nikitskiy, Julien Brault, Mathieu Leroux, Antoine Barbier, Fabrice Semond, CNRS-CRHEA, Université Côte d’Azur, Valbonne, 06560, France; Muhammad Khan, Hideki Hirayama, Fumiya Chugenji, Taiga Kirihara, RIKEN Cluster for Pioneering Research (CPR), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
This work investigates the optical properties of (Al,Ga)N heterostructures emitting between 310nm and 209nm. Photoluminescence (PL) analyses were conducted on thick epilayers, single and multiple quantum wells. Full width at half maximum of the PL, orientations and shapes of the on-side emission diagram, and PL intensity were analyzed by taking into account valence band symmetry, Quantum Confined Stark Effect, and 2D carrier localization.
This work was supported by ANR funding GANEX (ANR-11-LABX-0014) and DOPALGAN .
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16:15 - 16:30
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Manuscript ID. 0003
Paper No. 2025-Mon-S0509-O002
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| Chia-Yen Huang
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Direct observation of nanoscopic lattice distortion and composition inhomogeneity in AlGaN multiple-quantum wells
Chia-Yen Huang, National Yang Ming Chiao Tung University; Ying-Chun Chao, Hung-Wei Yen, National Taiwan University
We characterized two UVC light-emitting diode (LED) epi wafers by high-resolution scan transmission electron microscopy (HR-STEM) and atom probe tomography (APT). Geometry phase analysis with HR-STEM revealed the sample grown on the more compressively strained template possesses a more pronounced local lattice constant distortion in the multiple-quantum-well (MQW) region. APT further verified the local lattice distortion originated from the strain-induced Ga segregation in the MQW. The nanoscopic compositional fluctuation favors AlGaN growth front destabilization and triggers new defect nucleation, which explains the atomistic origin of strain-induced morphology and performance degradation in UVC LEDs.
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16:30 - 16:45
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Award Candidate (Paper Competition)
Manuscript ID. 0048
Paper No. 2025-Mon-S0509-O003
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| Jeong Kyun OH
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Enhanced Green Hydrogen Generation Using GO-GaN Photoanodes in Direct Seawater Splitting
Jeong-Kyun OH, Sung-Un Kim, Dae-Young Um, Min-Seok Lee, Cheul-Ro Lee, Yong-Ho Ra, . Division of Advanced Materials Engineering, College of Engineering, Jeonbuk National University (JBNU), Jeonju, Republic of Korea
Green hydrogen generation through photoelectrochemical water splitting (PEC-WS) is regarded as one of the most environmentally friendly hydrogen generation methods. III-nitride semiconductors are promising photoanode materials due to their tunable bandgap (UV to NIR) and favorable alignment with water redox potentials. However, their application in direct seawater PEC-WS is hindered by surface defects, limited surface area, and severe energy band bending. This study demonstrates that GO/GaN photoanodes enhance charge transport and improve photoelectrode stability through graphene oxide passivation, offering an effective strategy to overcome existing limitations and enable efficient hydrogen generation from direct seawater.
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16:45 - 17:00
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Award Candidate (Paper Competition)
Manuscript ID. 0104
Paper No. 2025-Mon-S0509-O004
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| Pham Tu Huynh
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Defects Visualization in GaN-based HEMTs with SiNx nano-mask by Cathodoluminescence Spectroscopy
Tu Huynh Pham, Nhu Quynh Diep, Jinji Dai, Quynh Trang Tran, Thi Bich Tuyen Huynh, Wu Ching Chou, Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan; Thi Thu Mai, Department of Advanced Materials Science and Nanotechnology, University of Science and Technology of Hanoi, Vietnam
The demand for high-power, high-frequency electronics drives GaN-based high electron mobility transistor (HEMT) development. To suppress threading dislocations (TDs) that cause leakage, SiNₓ nano-mask was incorporated into AlGaN/GaN HEMTs on Si(111). Effects of varying SiH₄ flow rates during MOCVD growth were studied. Cathodoluminescence spectroscopy visualized TDs density, confirmed uniformity, and assessed optical properties, supported by Raman and electrical characterization. At 50 sccm SiH₄, the defect-to-free-exciton emission ratio was minimized, and breakdown voltages improved (1710 V to 1780 V, 411 V to 448 V). Comprehensive understanding of SiNₓ nano-mask effects enables substantial improvements in GaN-based HEMT crystal quality and device performance.
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