新穎高效率混合型之奈米粒子光電元件-總計畫暨子計畫一：新穎高效率混合型之奈米粒子光電元件

Abstract

近年來，由於具有量子侷限效應與良好之光學吸收與放光特性，奈米粒子的應用發展迅速，若能有效利用其特殊的物理性質結合氮化鎵光電元件，將有助於提升氮化鎵光電元件之效率。本整合型計畫將以實現新穎奈米粒子結合氮化鎵光電元件為主，結合來自交大、成大和元智大學三所大學共同合作，以創新的技術進行新穎混合型之奈米粒子光電元件的開發，主要分為三部分，其一，在材料合成部分，經由微波輔助水熱化學合成法製備表面官能機修飾、發光顏色不同且具備高轉換效率之發光量子點與膠體奈米粒子。其二、於光電元件部分，在磊晶部分，將導入ex-situ nucleation layer結合奈米結構製作方式來達成所謂one step高晶體品質之GaN成長使其能降低GaN layer晶體的缺陷密度，並且設計各種結構包含奈米圖案化基板設計、磊晶成長品質的改善、表面的奈米結構與光子晶體結構，可提升氮化鎵光電元件之內部量子效率與外部量子效率。在雷射部分，使用不同晶格種類之二維光子晶體共振腔結合奈米粒子。而太陽能電池部分，透過量子點奈米粒子之光子下轉換效應與抗反射特性來達到提升微奈米結構氮化鎵太陽能電池之效率。其三、利用結構模擬與光學分析，搭配光性量測分析與探討，提升光源發光功率、指向性、使發光光譜之線寬降低和太陽能電池之效率，透過建立有效的數值模擬方法計算太陽能電池中膠體量子點吸收光譜與量子點間的能量轉移率與描繪量子點在實驗系統中複雜的光電行為，提供設計奈米粒子光電元件有用的物理證據。藉由本計畫將材料合成、元件製作分析與模擬設計整合，將可獲得混合型高效率新穎氮化鎵光電元件。

Recently, the development of the nano-particles has been widely studied due to the quantum confinement effect and excellent optical characteristic. By incorporating the nano-particles with the GaN-based devices, the conversion efficiency or quantum efficiency in GaN electro-optical device could be improved. In this project, we combine NCTU, NCKU, and YZU to develop nano-particles on GaN electro-optical device. We would perform a systematic research to develop the novel hybrid nano-particle electro-optical device including three sub-projects. First, various types of high-efficiency quantum dots (QDs) and colloidal nanoparticles with different emission colors are fabricated by the microwave-assisted hydrothermal synthesis. Second, we introduce ex-situ nucleation layer such as AlN combined with the nano-patterning technology to produce low dislocation GaN layer. Moreover, the different structures such as nano-patterned substrate design, epi-growth quality, nano-structures on surface, and photonic crystal are designed to increase the internal and external quantum efficiency. For the laser devices, we will design, fabricate and analyze high efficiency GaN-based photonic crystal resonant cavity with nanoparticles. Furthermore, the QDs with down-conversion and anti-reflection mechanisms were utilized to to enhance the power conversion efficiency of GaN solar cells. Third, the highly directional surface-emitting light source and high efficiency solar cells could be obtained by simulation, process techniques, optical measurement and analysis. After that, we would develop the computation techniques and analysis methods for studying the electronic structures, optical absorption spectra, and energy transfer dynamics of colloidal QDs embedded in hybrid solar-cell systems. This numerical calculation and physical analysis will be compared with experiment results and conducted to provide useful guidelines for developing QD-hybrid solar cell devices. Finally, the novel hybrid nano-particle electro-optical device could be achieved by the incorporating the novel materials, process techniques, optical measurement and simulation model analysis.