研究目的
To characterize the electronic properties of two distributed Bragg reflector (DBR) multilayer heterostructures composed of III-nitride layers using high-resolution monochromated STEM-EELS.
研究成果
The study significantly improves the understanding of the electro-optical properties of AlN/GaN and InAlN/GaN DBRs through detailed characterization using STEM-EELS. The results provide insights into the chemical composition, structural properties, and dielectric response of these heterostructures.
研究不足
The study is limited by the spatial and energy resolution of the STEM-EELS technique, and the complexity of the theoretical models used to interpret the data.
1：Experimental Design and Method Selection:
High-resolution monochromated STEM-EELS was used to characterize the electronic properties of AlN/GaN and InAlN/GaN DBRs. The EELS signal was treated using ZLP subtraction and deconvolution methods, and non-linear fitting tools complemented with theoretical modeling of the electron scattering distribution.
2：Sample Selection and Data Sources:
The heterostructures were grown by the group of E. Calleja at the Instituto de Sistemas Optoelectrónicos y Microtecnología (ISOM), from Universidad Politécnica de Madrid.
3：List of Experimental Equipment and Materials:
STEM-EELS with sub-nanometric spatial resolution and < 200 meV energy resolution, HAADF imaging, and Kramers–Kronig analysis tools.
4：Experimental Procedures and Operational Workflow:
EELS at sub-nanometric spatial resolution was used to assess the electronic properties. The log-ratio formula was used to calculate the relative thickness, related to the electron inelastic mean free path. Fitting of the bulk plasmon peak was performed using Lorentzian and Drude free-electron models.
5：Data Analysis Methods:
The energy position of the plasmon peak was related to the chemical composition variation through Vegard’s law. Information regarding the structural properties of the material was obtained from the lifetime of the oscillation. The dielectric response of the materials was extracted using Kramers–Kronig analysis.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
