CdSe螢光量子點於發光二極體的研究

Abstract

本論文探討CdSe/ZnS量子點做為發光二極體中的螢光媒介用以 製造白光源的可行性研究。量子點具有高品質的光電特性及原子般 的電子結構，本論文就CdSe/ZnS螢光量子點，分析其在發光二極體 上的光學特性、量子點的發光特性，探討不同光源激發量子點的發 光現象，以及在不同溫度下、不同電壓下量子點的發光效果。由於 電子躍遷能量隨著量子點尺寸的增大而減小，亦即發光波長隨著量 子點的增大而變長，我們將不同大小的量子點與樹脂混合後封裝， 以20 mA與3 V的條件驅動,利用發射波長為460 nm的藍光晶片激發 不同大小的量子點,而得到峰值為560 nm與610 nm的光譜曲線，分別 源自於兩種不同尺寸分佈的量子點。最後我們成功的製作出發白光 的螢光量子點二極體。

This research investigates the feasibility of using CdSe/ZnS quantum dots as phosphors in light emitting diode (LED) structures to work as white light LEDs. Basically, quantum dots own good optical and electronic properties and become a good candidate as a sort of light source. In this study, we investigate the optoelectronic properties of CdSe/ZnS quantum dots as function of temperature using photoluminescence technique and the characteristics of such fabricated white light LEDs under various operational conditions. By taking advantage of different light spectra resulted from different sized quantum dots due to quantum effect, we successfully fabricate white light LEDs with main peaks at 460 nm, originated from the blue light LED chip, and 560 nm and 610 nm which are attributed to the luminescence from 2.4 nm and 4.0 nm sized CdSe/ZnS quantum dots, respectively. The CIE diagrams of these while light LEDs is closed to those of popular white light LEDs which are made of blue light chips with YAG phosphors. To conclude, this study may be an important step in seeking an approach to make solid white light sources. Our results also provide a good foundation to those researchers / engineers in the field for further investigating some other kinds of quantum dots as luminescence agents in white light LEDs.