| DC 欄位 |
值 |
語言 |
| DC.contributor | 光電科學與工程學系 | zh_TW |
| DC.creator | 侯佳宏 | zh_TW |
| DC.creator | Chia-Hung Hou | en_US |
| dc.date.accessioned | 2010-4-21T07:39:07Z | |
| dc.date.available | 2010-4-21T07:39:07Z | |
| dc.date.issued | 2010 | |
| dc.identifier.uri | http://ir.lib.ncu.edu.tw:444/thesis/view_etd.asp?URN=93246015 | |
| dc.contributor.department | 光電科學與工程學系 | zh_TW |
| DC.description | 國立中央大學 | zh_TW |
| DC.description | National Central University | en_US |
| dc.description.abstract | 本論文旨在提升氮化鎵發光二極體之光萃取效率。第二章探討二維柱狀結構於氮化鎵發光二極體表面與光萃取效率的關係。吾人利用三維有限時域插分法計算俱二維柱狀結構之氮化鎵發光二極體的光萃取效率。模擬結果顯示，隨著結構深度的加深，對應的光萃取效率也隨的提高。在實驗上，吾人鋪排直徑為1.5 ?m的單層聚苯乙烯小球於氮化鎵發光二極體的表面做為蝕刻遮罩，經過乾式蝕刻後，週期為1.5 ?m的氮化鎵柱便形成於元件的表面。製作出來的氮化鎵柱高度分別為80 nm、120 nm及180 nm的發光二極體。在直流電流為20 mA注入下，不同柱高元件所對應的光功率增益分別為12.0%、19.1%及30.7%。此實驗的結果與模擬得到的結果趨勢相同。製作二維週期性表面結構於LED元件表面的取光機制可由k空間的圖形來解釋。由於氮化鎵磊晶層的折射指數大於藍寶石基板與空氣，使得從量子井所發出來的光大部份都侷限於氮化鎵層。於是吾人利用小球製作柱狀結構於氮化鎵發光二極體表面，只要滿足此式，|kn//+G|| zh_TW | |
| dc.description.abstract | In this dissertation, we focused on improving the light extraction efficiency (LEE) of the GaN-based light-emitting diodes (LEDs). In Chapter 2, we explored the dependence of rod-texturing effect on LEE of the GaN LEDs. Three-dimensional finite-difference time-domain (3D FDTD) was employed to calculate the LEE of the rod-textured LEDs. The simulation results revealed that the LEE increased with increasing the height of the rods which were formed on the surface of the LEDs. An experiment was carried out to prove the simulation results. We deposited a monolayer of polystyrene (PS) microspheres of the diameter of 1.5 ?m onto the surface of LEDs and these spheres were used to serve as etching mask to resist the dry etching process. The periodic patterns were transferred onto the surface of GaN-based LEDs. We had fabricated 3 different depths, which were 80 nm, 120 nm and 180 nm, in order to check relations between etching depth and LEE enhancement. Under 20 mA dc current injection, the output power enhancements were 12.0%, 19.1% and 30.7%. The experimental results displayed the same trend as the simulation results. The physical origin of extracting the light by fabricating the 2D periodical structure can be explained by k-space diagram. Large portion of light emitted by the active layer are guided in the GaN layer because the refractive index of GaN, 2.4, is larger than those of air and sapphire, which are 1 and 1.76, respectively. Each guided mode is featured with its own wavevector, kn//. When periodical structure is formed onto the surface of GaN, the periodical structure provides a reciprocal lattice vector, G, which can couple the kn//. Once the condition, |kn//+G|| en_US | |
| DC.subject | 奈米球 | zh_TW |
| DC.subject | 微米球 | zh_TW |
| DC.subject | 光萃取效率 | zh_TW |
| DC.subject | 氮化鎵發光二極體 | zh_TW |
| DC.subject | nanospheres | en_US |
| DC.subject | microspheres | en_US |
| DC.subject | light extraction efficiency | en_US |
| DC.subject | GaN LEDs | en_US |
| DC.title | 利用奈微米球於提升氮化鎵發光二極體之光萃取效率研究 | zh_TW |
| dc.language.iso | zh-TW | zh-TW |
| DC.title | Study of Improving the Light Extraction Efficiency of the GaN-based LEDs by using Microspheres or Nanospheres | en_US |
| DC.type | 博碩士論文 | zh_TW |
| DC.type | thesis | en_US |
| DC.publisher | National Central University | en_US |