本論文之研究主題係旨在製備具折射係數漸變微透鏡結構之氮化鎵發光二極體及利用水熱法(hydro-thermal growth, HTG)製備單晶氧化鋅薄膜應用於光電元件之光電及材料特性分析。:
本論文架構概分為兩個部分，第一部分主要分為理論模擬分析與實驗研究兩方面。理論模擬分析係透過光學模擬軟體(TracePro)分析不同尺寸之SU-8微透鏡對傳統氮化鎵發光二極體之光析出效率影響。由光學模擬結果顯示，微透鏡之柱狀直徑為8 m時，可獲得最佳之光析出效率改善；實驗研究係採用黃光微影製程製備SU-8柱狀結構於傳統氮化鎵發光二極體表面，再利用光阻與柱狀結構之吸附力及光阻本身之表面張力內聚於柱狀結構頂端形成球狀，進而完成SU-8微透鏡結構。從實驗結果顯示，具柱狀結構直徑8 m微透鏡之氮化鎵發光二極體元件於注入電流350 mA時，與傳統氮化鎵發光二極體相較，其光析出效率增加14.1%。由光學模擬結果與實驗結果證實本論文提出新穎結構(具折射係數漸變之SU-8微透鏡結構)可有效提升光析出效率。
本論文第二部份則為(一)利用水熱法於p-GaN或n-GaN表面進行氧化鋅薄膜(HTG)成長，(二)氧化鋅薄膜之材料特性分析與與(三)氧化鋅薄膜應用於光電元件之光電特性分析三個項目。經由調變時間、濃度及溫度等參數，我們成功於p-GaN與n-GaN表面製備出氧化鋅單晶薄膜，此研究過程係參酌試片SEM圖逐步建立最佳成長時間、濃度及溫度之參數。藉由XRD、EDS、TEM、霍爾量測與穿透率量測等多種材料分析，確認所製備的氧化鋅薄膜為一單晶結構；最後再將此單晶氧化鋅薄膜結構應用於傳統氮化鎵發光二極體表面，探討其對於傳統氮化鎵發光二極體元件之光電特性。

This thesis aims at the development of a surface roughness technique through using SU-8 photoresist microlens and an HTG ZnO film to improve the light output power (Lop) of GaN light-emitting diodes (LEDs). This thesis is divided into two parts. The first part focuses on opitical simulation and experimental study. TracePro was used to simulate the size effects of the SU-8 microlens on the light output efficiency of LEDs, which indicates that SU-8 microlens with 8 m in diameter for the cylinder portion could be the optimum design. Experiments have been conducted using photolithography process to form SU-8 microlens arrays on the surface of conventional GaN-based LEDs. Experimental results show an improvement in Lop of LEDs with 8 m Cylinder diameter microlens structure by 14.1% at 350 mA, as compared with that of the regular LEDs. The second part of this thesis is devoted to clarify the growth mechanism of ZnO thin film on GaN epilayer, material analysis and its application on LEDs for light output enhancement. Hydrothermal growth (HTG) method was employed to grow ZnO thin film on p-GaN and n-GaN surface. Effects of the growth time and temperature on the film structure and quality were examined. Material analysis using SEM, XRD, TEM and EDS were made and single crystallinity of the grown ZnO films was confirmed.

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