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Scandium Diffusion-Driven Defect Formation and Thermal Stability in GaInN/GaN Multiple Quantum Wells
Jiaxuan Peng1, Li Jiang1, Weifang Lu1,2
1Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, Department of Physics, Xiamen University, Xiamen361005, China.
ACS Applied Materials & Interfaces
|August 13, 2026
Summary
Scandium (Sc) diffusion into Gallium Indium Nitride (GaInN) quantum wells degrades optical properties. Annealing above 600°C causes Sc accumulation, generating nonradiative centers and reducing efficiency in ScAlMgO4-based devices.
Area of Science:
- Materials Science
- Semiconductor Physics
- Optoelectronics
Background:
- ScAlMgO4 (SAM) substrates provide lattice matching for long-wavelength GaInN emitters.
- Thermal stability of Sc-containing interfaces is crucial for epitaxial growth but poorly understood.
- Sc diffusion can negatively impact the performance of GaInN/GaN heterostructures.
Purpose of the Study:
- To investigate the intrinsic effects of Scandium (Sc) diffusion on GaInN/GaN multiple quantum wells (MQWs).
- To understand the impact of Sc diffusion on structural properties and carrier recombination dynamics.
- To elucidate the mechanisms behind Sc-induced optical degradation in SAM-based heterostructures.
Main Methods:
- Fabrication of Sc-capped GaInN/GaN MQWs to isolate Sc diffusion.
- Systematic variation of capping structures and annealing temperatures (600-900 °C).
- Characterization using cross-sectional scanning transmission electron microscopy (S-TEM) with energy-dispersive X-ray spectroscopy (EDX), photoluminescence (PL), time-resolved photoluminescence (TRPL), and temperature-dependent photoluminescence (TDPL).
- First-principles calculations to identify potential Sc-related defects.
Main Results:
- Sc preferentially incorporated into GaN barriers, preserving MQW periodicity at moderate temperatures.
- Annealing at 600 °C reduced defects and improved internal quantum efficiency (IQE).
- Significant degradation observed at 800 °C due to Sc redistribution and interface broadening, linked to nonradiative recombination centers (NRCs).
- Sc-VN complexes identified as potential Sc-related NRCs.
- Alloy inhomogeneity and enhanced carrier localization observed at 900 °C.
Conclusions:
- Sc diffusion is a primary cause of optical degradation in GaInN/GaN MQWs grown on SAM substrates.
- Optimizing annealing conditions and understanding Sc diffusion limits are critical for device performance.
- Insights into impurity effects and solid-state stability are provided for SAM-based nitride heterostructures.
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