多顆微型化氮化鎵發光二極體之研究

Investigation of Multiple Nitride-based Micro Light-Emitting Diodes

呂俊霖(Chun-Lin Lu)

指導教授 ： 郭政煌

國立交通大學/光電學院/光電系統研究所/碩士(2020年)

摘要

微型化藍光發光二極體和傳統藍光發光二極體相比之下，其光輸出功率在除以發光面積做規一化之前，微型化藍光發光二極體的光輸出功率遠小於傳統藍光發光二極體。因此本論文利用共N極共P極之電極設計整合三顆微型化發光二極體，希望能維持原本微型化發光二極體低導通電壓的特性，並藉由增加發光面積來提升整體的光輸出功率。從實驗結果可知，藍光發光二極體及紫外光發光二極體因電流擴散長度的不同以及元件電阻不同導致電流分流情形不同，因此將三顆微型化發光二極體進行整合後其光電特性截然不同:由理論計算得知藍光發光二極體之電流擴散長度為76μm，小於我們所設計的元件尺寸，再加上我們所設計的元件因為其內部三顆晶粒的電阻值不同導致電流分流後會集中在位於中間的晶粒，因此整合三顆微型化藍光發光二極體不僅會有單顆光強度分佈不均的問題，整體光強度分佈也會因為電流分流的影響導致位於中間的晶粒特別亮。在尺寸100μm、尺寸80μm和尺寸60μm的微型化藍光發光二極體，其整合三顆後的光輸出功率分別只有單顆的2.71倍、2.76倍和2.94倍，由於隨著元件尺寸縮小越接近藍光發光二極體之電流擴散長度，再加上元件內三顆晶粒的電阻值差異亦會越小，因此整合三顆後和單顆光輸出功率的差距隨著元件尺寸越小越接近三倍;紫外光發光二極體其電流擴散長度為728μm，則遠大於我們所設計的元件，再加上紫外光發光二極體其元件電阻比藍光發光二極體的約大了兩倍以上，因此電流經分流後的差異比例較藍光發光二極體小，因此整合三顆微型化紫外光發光二極體其光強度分佈明顯比整合三顆微型化藍光發光二極體均勻。在尺寸100μm、尺寸80μm和尺寸60μm的微型化紫外光發光二極體，其整合三顆後的光輸出功率分別是單顆的5.00倍、4.33倍和3.43倍，由於尺寸越大的元件越接近紫外光發光二極體的電流擴散長度，因此其光輸出功率也會越好。

關鍵字

藍光微型化發光二極體 ； 紫外光微型化發光二極體 ； 電流擴散長度 ； 整合微型化發光二極體

並列摘要

Compared with the blue conventional light-emitting diode (LED), the light output power of blue micro LED was much smaller than that of the blue conventional LED before dividing the light-emitting area for normalize. Therefore, in this study we used a common N and common P electrode configuration design to integrate three micro LEDs, expecting to maintain the low operation voltage characteristic of micro LED and improving the light output power by increasing the light-emitting area. The result was shown that due to the current spreading length of blue LED and ultraviolet LED were different, and different devices resistance leads to different current shunt situations, the optoelectronic characteristics of two LEDs were totally different. According to theoretical calculations, the current spreading length of blue LED was 76μm, which was smaller than the micro LED chip size. In addition, the devices we designed because of the different resistance of the three internal chips, the current would be concentrated in the middle chip after current shunted. Therefore, integrating three blue micro LEDs would not only cause non-uniform light intensity distribution of a single chip, the middle chip was also particularly bright due to the influence of current shunt. In the blue micro LEDs with the size of 100μm, 80μm and 60μm, the light output power after integrating three was only 2.71 times, 2.76 times and 2.94 times of a single one. Due to the reduction in chip size was closer to the current spreading length of the blue LED, and the resistance difference of the three chips in the devices would also be smaller, the difference of light output power between the integrated three and a single was closer to three times as the chip size got smaller. However, the current spreading length of ultraviolet LED was 728μm, which was larger than the micro LED chip size. In addition, the resistance of ultraviolet LED was more than twice of the blue LED, so the difference ratio of current after the current shunted was smaller than that of blue LED. As a result, the light intensity distribution of integrating three ultraviolet micro LEDs were significantly more uniform than integrating three blue micro LEDs. In the ultraviolet micro LEDs with the size of 100μm, 80μm and 60μm, the light output power after integrating three was 5.00 times, 4.33 times and 3.43 times of a single one. Due to the larger chip size was closer to the current spreading length of the ultraviolet LED, the light output power would also be better.

並列關鍵字

blue micro LED ； UV micro LED ； current spreading length ； integrate micro LEDs

參考文獻

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