Normandie University, GPM, UNIROUEN, INSA Rouen, CNRS , 76000 Rouen, France.
SuperSTEM STFC Daresbury Laboratories , Warrington WA4 4AD, United Kingdom.
Nano Lett. 2017 Jul 12;17(7):4261-4269. doi: 10.1021/acs.nanolett.7b01189. Epub 2017 Jun 27.
The localization of carrier states in GaN/AlN self-assembled quantum dots (QDs) is studied by correlative multimicroscopy relying on microphotoluminescence, electron tomography, and atom probe tomography (APT). Optically active field emission tip specimens were prepared by focused ion beam from an epitaxial film containing a stack of quantum dot layers and analyzed with different techniques applied subsequently on the same tip. The transition energies of single QDs were calculated in the framework of a 6-bands k.p model on the basis of APT and scanning transmission electron microscopy characterization showing that a good agreement between experimental and calculated energies can be obtained, overcoming the limitations of both techniques. The results indicate that holes effectively localize at interface fluctuations at the bottom of the QD, decreasing the extent of the wave function and the band-to-band transition energy. They also represent an important step toward the correlation of the three-dimensional atomic scale structural information with the optical properties of single light emitters based on quantum confinement.
通过依赖于微光致发光、电子断层扫描和原子探针断层扫描（APT）的相关多显微镜研究，GaN/AlN 自组装量子点（QD）中载体态的局域化。通过从包含量子点层堆叠的外延膜聚焦离子束制备了具有场发射尖端的样品，并随后在同一尖端上应用不同的技术对其进行了分析。基于 APT 和扫描透射电子显微镜特性，在 6 带 k.p 模型的框架中计算了单个 QD 的跃迁能量，表明可以获得实验和计算能量之间的良好一致性，从而克服了两种技术的局限性。结果表明，空穴有效地局域在 QD 底部的界面波动处，从而减小了波函数的范围和带带跃迁能量。它们还代表了朝着基于量子限制的单个发光体的三维原子尺度结构信息与光学性质的相关性迈出的重要一步。
