硒化鋅/碲化鋅量子點/硒化鋅第二型半導體結構之光學旋偏振特性研究

Abstract

本論文研究碲化鋅量子點/硒化鋅第二型結構之旋偏振特性，我們發現雖然本奈米異質結構並沒有包含磁性物質，然而螢光會展現不同的旋偏振特性。我們研究發現使用不同的波長的雷射激發光，可以使其樣品展現不同的螢光的旋偏振特性。這樣的獨特旋偏振性質，在這個發展已久且已經有成熟的半導體元件的材料中，添加了一個新的特性，相信這個研究結果對新穎半導體元件的開發必定有所貢獻。

Spin polarization of light emission arising from self-assembled ZnTe/ZnSe quantum dots grown by molecular beam epitaxy is investigated. It is found that the magnitude and sign of the degree of spin polarization can be drastically manipulated by excitation wavelength. The underlying mechanisms can be explained well based on the combination of band alignment, energy level splitting, as well as selection rule of optical transitions. The unique tunability of spin polarization of light emission by excitation wavelength adds an unprecedented feature to semiconductor materials, which have been studies for quite a long time. It is believed that the results obtained in this study will pave a key step for the development of optospintronics.