本篇論文中，我們成功地製作出以InGaN/GaN為多重量子井的藍光發光二極體，並且分析其光與電之特性。我們磊晶成長了七個不同的結構來探討其特性變化，其中包含傳統的發光二極體。我們加入AlGaN這種高能隙的材料來使得載子侷限在發光層中，以提高電子與電洞覆合的機率，進而提升二極體的亮度。此外，我們將利用InGaN/GaN的超晶格層所形成的二維電子雲(2-DEG)使得電流分佈較均勻，因此可以有效地降低順向導通電壓，且對亮度的提升也有明顯的改善。

　　此外，我們將使用以AlGaN/GaN為基礎的超晶格並且摻雜Mg來取代P型GaN。由於strain造成的壓電場會使得Mg之活化能有效降低。因此Mg-AlGaN/GaN SLs的電洞濃度會比一般的p-GaN高出十倍以上。實驗結果得知，使用上述的P型材料，可以得到較小的順向導通電壓，以及較高的亮度。除此之外，我們也改變多重量子井中Barrier的厚度，以及多重量子井的數目，來探討其對光電特性之影響。

　　製程方面，我們使用硏磨的方式將藍寶石基板做鏡面拋光，並且鍍上不同的金屬，來比較其對光的反射程度。實驗結果得知鍍上鈦有最好的反射率(58%)。我們將之應用在發光二極體的製程，對發光亮度有39%的提升。

　In this thesis, we have successfully
fabricated InGaN/GaN multiple-quantum
-wells (MQW) blue light emitting diodes and analyzed the electrical and optical characteristics. We grew seven different kinds of structures to discuss the characteristic variations of them. In order to get better carrier confine ability, we incorporate conventional LEDs with AlGaN which is a high bandgap material. Therefore, carrier can be confined in active region easily so as to increase the ratio of recombination of electrons and holes. By this, we can get better optical characteristics. Besides, utilizing InGaN/GaN super lattices (SLs) could form two dimension electron gas (2-DEG) and we can get better current spreading characteristics. So, we degrade forward turn on voltage efficiently and increase output power of our LEDs.

　Besides, we use Mg-AlGaN/GaN supperlattices (SLs) as p-GaN. It was known that lattice mismatch induced piezoelectric will decrease active energy of Mg. Therefore, using such material can have ten times hole concentration to general p-GaN. By the result of experience, lower forward turn on voltage (I=20 mA) and higher light of power will be achieved. Besides, we also change the thinness of barrier of MQWs and the numbers of MQWs to discuss the influence of electrical and optical characteristic.

　In process, we polish the backside of wafer and evaporate different kind of metal on it to compare their reflectance .As result, we find that Ti evaporated on the backside of wafer has batter reflectance (58%) compared to other metal. So we utilize the result in our process of LEDs. It can increase 39% output power of light.

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