论文标题
巨型壳CDSE/CDS纳米晶体：谐振拉曼光谱调查的激子耦合与壳声子耦合
Giant-Shell CdSe/CdS Nanocrystals: Exciton Coupling to Shell Phonons Investigated by Resonant Raman Spectroscopy
论文作者
论文摘要
半导体纳米晶体中激子与声子之间的相互作用在激子能量谱和动力学中起着至关重要的作用，因此在其光学特性中起着至关重要的作用。我们通过谐振拉曼光谱学研究了巨型壳CDSE/CDS核壳纳米晶体中的Incon2声子耦合。 Huang-rhys参数通过CD的纵向光（LO）语音的强度比与其第一个多肢体（2LO）副本进行评估。我们在从CDS壳吸收到良好的CDS壳带边缘上方的范围内使用了四个不同的激发波长，以深入了解具有高能激发型转换的CDS LO唱片的共振效应。与各向异性棒状棒形的点（DIR）结构相比，各向同性球形巨型壳纳米晶体始终显示出更强的激子 - phonon耦合，而2Lo/Lo强度比降低了接近CDS带边缘的激发波长的降低。球形巨型壳纳米晶体中强的激子 - 音波耦合可能与电子波函数的离域化有关。此外，我们使用超低于异晶晶带隙以下的激光能量，观察到GS纳米晶体的径向呼吸模式及其通过非谐波激发的超级频率拉曼光谱及其泛音，并高显示较高顺序的差异
The interaction between excitons and phonons in semiconductor nanocrystals plays a crucial role in the exciton energy spectrum and dynamics, and thus in their optical properties. We investigate the exciton2 phonon coupling in giant-shell CdSe/CdS core-shell nanocrystals via resonant Raman spectroscopy. The Huang-Rhys parameter is evaluated by the intensity ratio of the longitudinal-optical (LO) phonon of CdS with its first multiscattering (2LO) replica. We used four different excitation wavelengths in the range from the onset of the CdS shell absorption to well above the CdS shell band edge to get insight into resonance effects of the CdS LO phonon with high energy excitonic transitions. The isotropic spherical giant-shell nanocrystals show consistently stronger exciton-phonon coupling as compared to the anisotropic rod-shaped dot-in-rod (DiR) architecture, and the 2LO/LO intensity ratio decreases for excitation wavelengths approaching the CdS band edge. The strong exciton-phonon coupling in the spherical giant-shell nanocrystals can be related to the delocalization of the electronic wave functions. Furthermore, we observe the radial breathing modes of the GS nanocrystals and their overtones by ultralow frequency Raman spectroscopy with nonresonant excitation, using laser energies well below the band gap of the heteronanocrystals, and highlight the differences between higher order
