标题: 自组式量子点偏振萤光之理论研究
Theoretical studies of polarized photoluminescence
作者: 尤文廷
You, Wen-Ting
郑舜仁
Cheng, Shun-Jen
电子物理系所
关键字: 激子;自组式量子点;偏振萤光;交换能;价电带混成;光学异相性;exciton;self-assembled quantum dots;polarized photoluminescence;exchange energy;valence-band mixing;optical anisotropy
公开日期: 2009
摘要: 本篇文章主要是探讨激子(电子-电洞对)在自组式量子点中所释放的旋光。文章中利用 多能带理论以及波包近似法理解激子中电子和电洞的性质,接着将于系统中引入重电洞、轻电洞耦合并使用费米黄金定律了解其对激子所释放出旋光的影响。而关于重电洞、轻电洞的耦合包含两大因素:(1)Luttinger-Kohn Hamiltonian因为量子点得不对称性(形状、应力)而产生耦合 (2)激子间的交换能。结果发现其耦合效应的强弱会影响线性偏振光的能量劈裂大小,甚至可以发现有一个临界点(能量简并)会造成X、Y方向线偏振光能量反转;量子点的不对称性会造成光学的异相性;激子能量劈裂差距和光学异相性程度(极化率)具有成正比的关系。
This thesis presents a theoretical study of polarized photoluminescence spectrum of a single spin exciton confined in a strained self-assembled quantum dot (QD). The electronic structure of an exciton in QD is studied in the framework of four-band strain model. The time-dependent perturbation theory is employed to calculate the polarized emission spectrum of strained quantum dot. The study shows that the effect of heavy- and light-hole (HH and LH) mixing is especially pronounced in quantum dots with lateral shape deformation and is essential in the polarized photoluminescence spectrum of QD. The HH-LH mixing results in pronounced optical anisotropy and substantially renormalize the magnitude of fine structure splitting between the bright exciton states of deformed QD.
URI: http://140.113.39.130/cdrfb3/record/nctu/#GT079621541
http://hdl.handle.net/11536/42456
显示于类别:Thesis


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