本論文主要利用外加偏壓15 V、20 V、30 V以及130 V進行電化學氧化蝕刻N型氮化鎵(n-GaN) 模板產生形貌為樹枝狀的奈米孔洞(Nanoporous) 後，再成長(Regrowth) LED 結構觀察其光電特性，而經由再成長後會發生再結晶之現象，使得原本為形貌為樹枝狀奈米孔洞變化成為橢圓型及圓形，藉由樹枝狀的奈米孔洞(Nanoporous) 形成空氣洞(Air void) 後，使電子與電洞復合後產生的光在LED 內部有更多的機會散射使出光量增加，進而提高光輸出功率。與無結構的基板的LED (Conventional LED) 比較，在電流20 mA 注入下，15 V、20 V、30 V以及130 V 的光輸出功率分別為 7.58 mW、8.08 mW、10.90 mW 、5.44 mW 與10.99 mW ，可知15 V、20 V以及130 V相較於Conventional LED 的7.58 mW 分別增加了6.6 %、43.8%、45.0 %，而LED Ⅳ 推測因為再成長後試片表面變黑導致吸光的情形較劇烈，因此發光強度是衰減了28.2%。
由於利用外加偏壓進行電化學氧化蝕刻後的試片，經過高溫再成長後的試片以肉眼判斷表面呈現黑色，試片變黑的程度與奈米孔洞的大小及密度成正比，而試片表面變黑會造成光被吸收，因此希望可以透過MOVPE 改變腔體的溫度、氣體流量、熱處理的時間以及透過二次熱處理和再成長的方式改善在不同偏壓下進行電化學蝕刻的試片之表面變黑的現象。其中在上述方法中，我們利用MOVOE 改變腔體環境中的氫氣與氮氣流量後進行熱處理，原先環境氣體通入8 slm 的氨氣與30 slm 的氫氣，以肉眼觀看試片表面變黑的情形相當明顯，而當環境氣體通入4 slm 的氨氣與34 slm 的氫氣是可得到最明顯的改善。其中試片變黑的程度我們利用灰階色卡量化試片表面變黑的程度，因此可以區別出各試片表面變黑的程度。

In this thesis, we investigated the nanoporous n-type gallium nitride (n-GaN) template by electrochemical etching process. We investigated the photoelectric characteristics of regrown complete LEDs. In this experiment, we using the bias 15 V, 20 V, 30 V and 130 V operated electrochemical etching process. Under 20 mA current injection, the light output power were 7.58 mW, 8.08 mW, 10.90 mW, 5.44 mW and 10.99 mW, respectively. The light output power of conventional LED (normal LED) was 7.58 mW. Comparing the light output power conventional LED with sample that after electrochemical etching process using bias 15 V, 20 V and 130 V enhanced 6.6 %、43.8% and 45.0 %, respectively. But sample of after electrochemical etching process using bias 30 V decreased 28.2%, because surface of sample became black like. The black like absorbing light led to light output power degradation. On the other hand, under 20 mA current injection, the turn on voltage of conventional LED was 2.80 V, and after electrochemical etching process using bias 15 V, 20 V, 30 V and 130 V were 2.825 V, 2.825 V, 2.825 V and 2.825 V, respectively. Sample of after electrochemical etching process were slightly higher by 0.025 V. It could impute to defects increasing after electrochemical etching process. So they could not deposit very well as conventional LED during regrowth process by MOVPE.
To resolve absorbing light led to light output power degradation from surface of sample became black like. The condition of MOVPE chamber was modification that including temperature, time of annealing and gas flow of chamber. We using process that twice annealing and adjusting recipe of regrowth to decrease level of surface black like. Modifying gas flow in chamber was the best method to decrease level of surface black like. The gas flow of chamber changed from NH3: 8slm, H2: 30slm to NH3: 4 slm, H2: 34 slm.

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