本實驗中首先研究高鋁含量之氮化鋁鎵於硝酸中進行選擇性電化學蝕刻後之孔洞形態與蝕刻深度，先比較在不同摻雜濃度下孔洞孔徑、蝕刻深度、孔洞率之差異，摻雜濃度越高在大電壓下進行電化學蝕刻越早發生蝕刻停止(Etching stop)，因為施加偏壓為大電壓時，試片產生氧化物速度較快，推測是形成緻密的一層氧化物薄膜(Al2O3)，導致試片與電解液無法形成液半接面而使反應終止。因此在電壓較小的條件下進行電化學蝕刻較不易發生蝕刻終止，可能原因為生成緻密薄膜的速度較慢。因此高鋁含量多孔氮化鋁鎵若蝕刻孔洞孔徑大則蝕刻深度淺，相反地，若蝕刻孔洞孔徑小則蝕刻深度較深，所以在高鋁含量氮化鋁鎵使用電化學蝕刻製成分佈式布拉格反射器時，若要反射率高則元件為小尺寸，若要元件為大尺寸則要犧牲反射率，光萃取率效果可能有限。因此將多孔氮化鋁鎵布拉格分佈式反射器結構引入發光二極體中，提升光萃取率後，在相同電流密度下發光強度(mW)得以提升，但是在量測4155電特性時，因為串聯電阻的效應蝕刻成孔洞後會增加電阻值，所以與標準元件比較在電流等級為20mA下，電壓會變大。而在進行完電化學蝕刻後在N-contact處，可能會形成氧化物(Ga2O3、Al2O3)，將試片分別浸泡鹽酸與磷酸蝕刻氧化物，使金屬能完全接觸於半導體上而不會因為氧化物導致形成蕭特基接觸。在製成多孔氮化鋁鎵分佈式布拉格反射器之深紫外發光二極體後，藉由提高光萃取率增加發光亮度，但是多孔氮化鋁鎵會提高電阻值，所以在量測電性時，順向偏壓之Vf會增大，漏電流也會變大，是因為串聯電阻概念引入。外部量子轉換效率提高是因為光萃取率提升進而也提高。

In this experiment, the pore morphology and etching depth of AlGaN with high Al content after selective electrochemical etching in nitric acid. Firstly, the difference of pore size, etching depth and porosity at different doping concentrations were compared. The higher impurity concentration, the earlier the electrochemical etching is performed at high voltage. The etching stops because the applied bias voltage is a high voltage. It is presumed that a dense oxide film is formed to cause the test piece and the electrolyte.Therefore, electrochemical etching is less likely to occur at a lower voltage, which may be caused by a slower rate of formation of a dense film. Therefore, the high aluminum content porous aluminum gallium nitride has a shallow etching depth if the porous diameter of the etching is large. In the case of a Bragg reflector, if the reflectance is high, the component is small. After the light extraction rate is increased, the light-emission intensity is improved at the same current density, so when measuring the electrical property The Vf of the forward bias voltage increases, because the series resistance concept is introduced. The external quantum conversion efficiency is improved because of the light extraction rate is increased.

References in Chapter 1
[1] Liang Zhang,Jianchang Yan,Qingqing Wu,Yanan Guo,Chao Yang, Tongbo Wei, Zhiqiang Liu, Guodong Yuan,Xuecheng Wei, Lixia Zhao, Yun Zhang, Jinmin Li and Junxi Wang,Improved crystalline quality of Al-rich n-AlGaN by regrowth on nanoporous template fabricated by electrochemical etching, J. Nanophoton. 12(4), 043509 (2018)
[2] Feng-Hsu Fan, Zun-Yao Syu, Chia-Jung Wu, Zhong-Jie Yang, Bo-Song Huang, Guan-Jhong Wang, Yung-Sen Lin, Hsiang Chen, Chyuan Hauer Kao & Chia-Feng Lin, Ultraviolet GaN Light-Emitting Diodes with Porous-AlGaN Reflectors, Received: 30 August 2016 Accepted: 30 May 2017 Published:10 July 2017
[3] 李溱錙碩士碩士論文，國立成功大學光電科學與工程學系，光電產業研發碩士專班碩士論文，以N型氮化鎵為模板利用電化學蝕刻形成奈米孔洞改善氮化鎵發光二極體之光萃取效率
[4] Yu Zhang, Benjamin Leung, and Jung Han,” A liftoff process of GaN layers and devices through nanoporous transformation”, Appl. Phys. Lett. 100, 181908 (2012);
[5] John C. Jarman , Tongtong Zhu* , Peter H. Griffin , and Rachel A. Oliver,” Light-output enhancement of InGaN light emitting diodes regrown on nanoporous distributed Bragg reflector substrates”, Japanese Journal of Applied Physics 58, SCCC14 (2019)
[6] Christopher D. Yerino, Yu Zhang,1 Benjamin Leung, Minjoo L. Lee, Ta-Cheng Hsu,Chun-Kai Wang, Wei-Chih Peng, and J. Han, Shape transformation of nanoporous GaN by annealing: From buried cavities to nanomembranes, Department of Electrical Engineering, Yale University, New Haven, Connecticut 06520, USA
[7] Danti Chen, and Jung Han,High reflectance membrane-based distributed Bragg reflectors for GaN photonics, Citation: Appl. Phys. Lett. 101, 221104 (2012), Published by the American Institute of Physics

[8] Saadat Mishkat-Ul-Masabih, Ting Shan Luk, Ashwin Rishinaramangalam, Morteza Monavarian, Mohsen Nami,and Daniel Feezell,Nanoporous distributed Bragg reflectors on free-standing nonpolar m-plane GaN,Citation: Appl. Phys. Lett. 112, 041109 (2018); Published by the American Institute of Physics
[9] Chongchong Zhao , Xiaokun Yang , Lüyang Shen , Caina Luan , Jianqiang Liu , Jin Ma ,Hongdi Xiao,Fabrication and properties of wafer-scale nanoporous GaN distributed Bragg reflectors with strong phase-separated InGaN/GaN layers, Journal of Alloys and Compounds 789 (2019)
[10] Yu Zhang, Sang-Wan Ryu, Chris Yerino, Benjamin Leung, Qian Sun, Qinghai Song, Hui Cao,and Jung Han, A conductivity-based selective etching for next generation GaN devices, Phys. Status Solidi B 247, No. 7, 1713–1716 (2010)
[11] Cheng Zhang, Ge Yuan, Alexander Bruch, Kanglin Xiong, z Hong X. Tang, and Jung Han, Toward Quantitative Electrochemical Nanomachining of III-Nitrides, Journal of The Electrochemical Society, 165 (10) E513-E520 (2018)

References in Chapter 2

[1] Cheng Zhang, Ge Yuan, Alexander Bruch, Kanglin Xiong, z Hong X. Tang, and Jung Han, Toward Quantitative Electrochemical Nanomachining of III-Nitrides, Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511, USA, Journal of The Electrochemical Society, 165 (10) E513-E520 (2018)
[2] J. W. Seo, C. S. Oh, H. S. Cheong, J. W. Yang,C. J. Youn and K. Y. Lim,UV-Assisted Electrochemical Oxidation of GaN, Department of Semiconductor Science and Technology/Semiconductor Physics Research Center, Chonbuk National University, Chonju 664-140, (Received 23 April 2002, in _nal form 8 November 2002)
[3] 李溱錙碩士碩士論文, 以N型氮化鎵為模板利用電化學蝕刻形成奈米孔洞改善氮化鎵發光二極體之光萃取效率，國立成功大學光電科學與工程學系，光電產業研發碩士專班碩士論文
[4] Hongqiang Lu, Ziming Wu, and lshwara Bhat,Photoassisted Anodic Etching of Gallium Nitride, Department of Electrical, Computer, and System Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA, J. Electrochem. Soc. 1997
[5] Danti Chen, and Jung Han,High reflectance membrane-based distributed Bragg reflectors for GaN photonics,Citation: Appl. Phys. Lett. 101, 221104 (2012), Published by the American Institute of Physics
[6] Saadat Mishkat-Ul-Masabih, Ting Shan Luk, Ashwin Rishinaramangalam, Morteza Monavarian, Mohsen Nami,and Daniel Feezell,Nanoporous distributed Bragg reflectors on free-standing nonpolar m-plane GaN,Citation: Appl. Phys. Lett. 112, 041109 (2018); Published by the American Institute of Physics
[7] Chongchong Zhao , Xiaokun Yang , Lüyang Shen , Caina Luan , Jianqiang Liu , Jin Ma ,Hongdi Xiao ,Fabrication and properties of wafer-scale nanoporous GaN distributed Bragg reflectors with strong phase-separated InGaN/GaN layers, Journal of Alloys and Compounds 789 (2019)
[8] Ali But ,Multilayer dielectric stack Notch filter for 450-700 nm wavelength spectrum, Conference Paper (PDF Available) • January 2017
[9] Cheng Zhang,Sung Hyun Park, Danti Chen, Da-Wei Lin,Wen Xiong,Hao-Chung Kuo,Chia-Feng Lin, Hui Cao, and Jung Han, Mesoporous GaN for Photonic Engineering-Highly Reflective GaN Mirrors as an Example, ACS Photonics 2015
[10] Jasbinder Sanghera, Catalin Florea, Lynda Busse, Brandon Shaw, Fritz Miklos, and Ishwar Aggarwal, Reduced Fresnel losses in chalcogenide fibers by using anti-reflective surface structures on fiber end faces, Optics Express Vol. 18,Issue 25,pp. 26760-26768,(2010)

References in Chapter 3

[1]汪建民等人，材料分析，中國材料科學學會(1998)