本論文提出有關於提升氮化鎵發光二極體出光效率之設計。我們證實了一些解決方案以提升光輸出亮度和降低正向電壓的方式來實現高效率發光二極體。這些效率提升的方法包含電流擴散改善、粗糙表面平坦化、晶粒側壁粗化、藍寶石基板崁入空氣孔隙。
首先，我們提出一個簡單的方法，藉由在晶粒的長邊方向加入金屬導線以提升側向發光型氮化鎵發光二極體的電流擴散。經由金屬導線的加入，發光二極體的20毫安輸出光功率可由8.54毫瓦提升至9.2毫瓦。而且我們發現經由化學法把金屬導線的厚度局部減薄後，可進一步把光輸出功率提升至9.68毫瓦。這些改善可歸因於發光二極體有著更均勻的電流分布。
接著，我們仍關注於發光二極體的表面，提出一個方法可提升具有粗糙表面的氮化鎵發光二極體之性能。使用氫氧化鉀溶液選擇性地將P電極下方區域平坦化，我們發現這可以降低正向電壓和提高氮化鎵發光二極體的輸出光功率。而且在光電轉換效率方面，所提出的發光二極體相較於具有粗糙表面的傳統發光二極體多出10.3％；相較於具有平坦面的傳統發光二極體多出33.9％。此外，使用選擇性氫氧化鉀蝕刻將不會降低發光二極體的衰減效應。
接著，將應用雷射切割技術。我們提出一個簡單的位移式雷射隱形切割來提升氮化鎵發光二極體的輸出光功率。相較於傳統只有使用奈秒雷射於正面切割的方法，我們在背面的不同位置額外執行了二次皮秒雷射切割。我們發現使用位移式雷射隱形切割不會降低元件的電特性,且可以有效地提升發光二極體的輸出光功率由132.34毫瓦增加至139.11毫瓦。同時發現此提升應當歸因於藍寶石基板粗化所帶來的出光效率增加。
最後，我們證實了經由多重雷射隱形切割法所製作的空氣孔隙來增強氮化鎵發光二極體輸出光功率。相較於傳統只有使用奈秒雷射於正面切割的方法，我們在背面的不同位置額外執行了多重皮秒雷射切割。我們發現使用多重雷射隱形切割不會降低元件的電特性,且可以有效地提升發光二極體的輸出光功率由166.66毫瓦增加至176.02毫瓦。同時發現此提升應當歸因於崁在藍寶石基板內部的空氣空隙,其造成光線強反射與更改方向以使出光效率增加。

The designs of enhancement in light extraction efficiency for GaN-Based LED were proposed in the dissertation. We demonstrated some solutions for realizing highly efficient GaN-based LEDs to improve the light output power and reduce the forward voltage. These enhancement approaches include the current spreading improvement, rough surface smoothing, chip sidewall surface texturing, and sapphire embedded air-void.
First, we propose a simple method to enhance current spreading of GaN-based side-view light-emitting diodes (LEDs) by adding a metallic stripe across the long side of the chip. It was found that 20 mA output power of the LED could be enhanced from 8.54 to 9.2 mW by adding the metallic stripe. It was also found that further the LED output power could be enhanced to 9.68 mW by partially thinning down the metallic stripe chemically. These improvements could be attributed to the more uniform current distribution across the LED chip.
Then, we keep focus on the top surface of LEDs. A simple method was proposed to enhance the performances of GaN-based light-emitting diodes (LEDs) with rough surface. By using KOH to selectively smooth the area beneath the p-contact pad, it was found that we could reduce the forward voltage and enhance output power of the GaN-based LEDs. It was also found that wall-plug efficiency (WPE) of the proposed LEDs was 10.3% larger than that of the conventional LEDs with rough surface and 33.9% larger than that of the conventional LEDs with flat surface. Furthermore, it was found that the use of selective KOH etching will not degrade drooping effect of the LEDs.
Then, the laser dicing technology will be applied. We propose a simple shifted laser stealth dicing (shifted-LSD) method to enhance output power of GaN-based blue light-emitting diodes (LEDs). Compared with the conventional method with only one nanosecond laser scribing from the front side, we performed two additional picosecond laser scribing on different positions of the backside surface. It was found that we could effectively enhance the LED output power from 132.14 to 139.11 mW using the shifted-LSD without degrading the electrical properties of the devices. It wa also found such enhancement should be attributed to the enhanced LEE from the roughened sapphire substrate.
Finally, we demonstrate the air voids structure fabricated by multiple laser stealth dicing (multi-LSD) method to enhance output power of GaN-based blue light-emitting diodes (LEDs). Compared with the conventional method with only one nanosecond laser scribing from the front side, we performed additional multiple picosecond laser scribing on the backside surface. It was found that we could effectively enhance the LED output power from 166.66 to 176.02mW using the multi-LSD without degrading the electrical properties of the devices. It was also found such enhancement should be attributed to the enhanced LEE from the strong light reflection and redirection by air-voids within sapphire substrate.

Chapter 1.
[1] S. Nakamura, M. Senoh, N. Iwasa and S. Nagahama, “High-power InGaN single-quantum-well-structure blue and violet light-emitting diodes”, Appl. Phys. Lett., Vol. 67, pp. 1868-1870 (1995).
[2] S. J. Chang, W. C. Lai, Y. K. Su, J. F. Chen, C. H. Liu and U. H. Liaw,“InGaN/GaN multiquantum well blue and green light emitting diodes”, IEEE J. Sel. Top. Quan. Electron., Vol. 8, pp. 278-283 (2002).
[3] Y. J. Lee, J. M. Hwang, T. C. Hsu, M. H. Hsieh, M. J. Jou, B. J. Lee, T. C. Lu, H. C. Kuo and S. C. Wang, “Enhancing the output power of Gain-based LEDs grown on wet-etched patterned sapphire substrates”, IEEE Photon. Technol. Lett., Vol. 18, pp. 1152-1154 (2006).
[4] S. Nakamura and G. Fasol, The Blue Laser Diode (Springer, Berlin, 1997).
[5] T. C. Wen, S. J. Chang, L. W. Wu, Y. K. Su, W. C. Lai, C. H. Kuo, C. H. Chen, J. K. Sheu and J. F. Chen, “InGaN/GaN tunnel injection blue light-emitting diodes”, IEEE Trans. Electron. Devices., Vol. 49, pp. 1093–1095 (2002).
[6] L. W. Wu, S. J. Chang, T. C.Wen, Y. K. Su, W. C. Lai, C. H. Kuo, C. H. Chen and J. K. Sheu, “Influence of Si-doping on the characteristics of InGaN/GaN multiple quantum well blue light-emitting diodes”, IEEE J. Quantum. Electron., Vol. 38, pp. 446–450 (2002).
[7] C. H. Kuo, S. J. Chang, Y. K. Su, J. F. Chen, L. W. Wu, J. K. Sheu, C. H. Chen and G. C. Chi, “InGaN/GaN light emitting diodes activated in 122 O ambient”, IEEE Electron. Device. Lett., Vol. 23, pp. 240–242 (2002).
[8] T. Mukai, M. Yamada and S. Nakamura, “Characteristics of InGaN-based UV/blue/green/amber/red light-emitting diodes”, Jpn. J. Appl. Phys., Vol. 38, pp. 3976–3981 (1999).
[9] I. Akasaki and H. Amano, “Crystal growth and conductivity control of group III-nitride semiconductors and their applications to short wavelength light emitters”, Jpn. J. Appl. Phys., Vol. 36, pp. 5393–5408 (1997).
[10] S. Nakamura, T. Mukai and M. Senoh, “Candela-class high brightness InGaN/AlGaN double hetrostructure blue light emitting diodes”, Appl. Phys. Lett., Vol. 64, pp. 1687–1689 (1994).
[11] R. Juza and H. Hahn, Anorg. Allegem Chem., Vol. 234, pp. 282, 1940.
[12] H. Amano, N. Sawaki, and I. Akasaki Toyoda, “Metalorganic vapor phase epitaxial growth of a high quality GaN film using an AlN buffer layer”, Appl. Phys. Lett., Vol. 48, pp. 353-355, 1986.
[13] S. Nakamura, M. Senoh, S. Nagahama and Y. Sugimoto, “InGaN-Based Multi-Quantum-Well-Structure Laser Diodes”, Jpn. J. Appl. Phys. 35, L74-L76, 1996.
[14] S. Nakamura, “GaN Growth Using GaN Buffer Layer”, Jpn. J. Appl. Phys. 30, L1705, 1991.
[15] S. Nakamura, T. Mukai, M. Senoh and N. Iwasa, “Thermal Annealing Effects on P-Type Mg-Doped GaN Films”, Jpn. J. Appl. Phys. 31, L139-L142, 1992.
Chapter 2.
[1] S. Nakamura, M. Senoh, S. I. Nagahama, N. Iwasa, T. Yamada, T. Matsushita, H. Kiyoku and Y. Sugimoto, “InGaN-Based Multi-Quantum-Well-Structure Laser Diodes”, Jpn. J. Appl. Phys., Vol. 35, pp. L74-L76, 1997.
[2] H. Amano, M. Kito, K. Hiramatsu and I. Akasaki, “P-Type Conduction in Mg-Doped GaN Treated with Low-Energy Electron Beam Irradiation (LEEBI)”, Jpn. J. Appl. Phys., Vol. 28, pp. L2112-L2114, 1989.
[3] S. Nakamura, T. Mukai, M. Senoh and N. Iwasa, ” Thermal Annealing Effects on P-Type Mg-Doped GaN Films”, Jpn. J. Appl. Phys., Vol. 31, pp. L139-L141, 1992.
[4] I. Akasaki and Hiroshi, “Breakthroughs in Improving Crystal Quality of GaN and Invention of the p–n Junction Blue-Light-Emitting Diode”, Jpn. J. Appl. Phys.,Vol. 45, No. 12, pp. 9001-9010, 2006.
[5] S. Nakamura, M. Senoh, N. Iwasa and S.I. Nagahama, “High-Brightness InGaN Blue, Green and Yellow Light-Emitting Diodes with Quantum Well Structures”, Jpn. J. Appl. Phys., Vol.34, L797-L799, 1995.
[6] C. H. Ko, Y. K. Su, S. J. Chang, T. M. Kuan, C. I. Chiang, W. H. Lan, W. J. Lin and J. Webb, “P-Down InGaN/GaN Multiple Quantum Wells Light-Emitting Diode Structure Grown by Metal-Organic Vapor-Phase Epitaxy”, Jpn. J. Appl. Phys., Vol. 41, 2489-2492, 2002.
[7] T. C. Wen and W. I. Lee, “Influence of Barrier Growth Temperature on the Properties of InGaN/GaN Quantum Well”, Jpn. J. Appl. Phys., Vol. 40, 5302-5303, 2001.
[8] J. K Sheu, C. J Pan, G. C. Chi, C. H. Kuo, L. W Wu, C. H. Chen, S. J. Chang and Y. K. Su, “White-light emission from InGaN-GaN multi quantum-well light-emitting diodes with Si and Zn codoped active well layer”, IEEE Photon. Technol. Lett., Vol. 14, No. 4, pp. 450-452, 2002.
[9] H. P. Maruskas and J. J. Tietjen, Appl. Phys. Lett. Vol. 15 (1969) 327
[10] H. M. Manasevit, “Single-crystal gallium arsenide on insulating substrates,” Appl. Phys. Lett., vol. 12, no. 4, pp. 156–159, 1968.
[11] H. M. Manasevit and W. I. Simpson, “Single-crystal silicon on sapphire substrate,” J. Appl. Phys., vol. 35, no. 4, pp. 1349–1351, 1964.
[12] I. Adessida, A. Mahajan, E. Andideh, M.A. Kahn, D.T. Olson, and J.N. Kuznia, “Reactive ion etching of gallium nitride in silicon tetrachloride plasmas”, Appl. Phys. Lett., 63, 2777, 1993.
[13] S.J. Pearton, C.R. Abernathy, F. Ren and J.R. Lothian, “Dry and wet etching characteristics of InN, AlN, and GaN deposited by electron cyclotron resonance metalorganic molecular beam epitaxy”, J. Vac. Sci. Technol., Vol. 11, 1772, 1993.
[14] R.J. Shul, G.B. McClellan, S.A. Casalnuovo, D.J. Rieger, “Inductively coupled plasma etching of GaN”, Appl. Phys. Lett., 69, 1119, 1996.
[15] I. W. Shockley, Research and Investigation of Inverse Epitaxial UHF Power Transistors, Report No. ALTOR-64-207. Air Force Atomic Laboratory, Wright Patterson Air Force Base, Ohio (1964).
[16] ESD Association standard test method for electrostatic discharge sensitivity testing Human Body Model (HBM) component level (ANSI/ESD5.1-2001)
[17] X. Guo and E. F. Schubert, “Current crowding and optical saturation effects in GaInN/GaN light-emitting diodes grown on insulating substrates,” Appl. Phys. Lett., vol. 78, p. 3337-3339, 2001.
[18] Billeb A., Grieshaber W., Stocker D., Schubert E. F. and Karlicek R. F. Jr., “Microcavity effects in GaN epitaxial films and in Ag/GaN/sapphire structures”, Appl. Phys. Lett., 70, 2790, 1997.
[19] A. A. Bergh, M. Hill, R. H. Saul, and S. Plains, U.S. Patent No. 3,739,217 (1973).
[20] T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the light extraction efficiency of GaN-based light-emitting diodes via surface roughening”, Appl. Phys. Lett. Vol. 84, pp. 855-857, 2004.
[21] P. P. Pronko, S. K. Dutta, J. Squier, J. V. Rudd, D. Du, G. Mourou: “Machining of sub-micron holes using a femtosecond laser at 800nm”, Optics Comm., 114, pp. 106-110 (1995)
[22] J. M. Lee, K. Y. Um. and K. G. Han, J. H. Jang and T. K. Yoo ” Scribing and cutting of sapphire wafer with Q-switched Nd:YAG laser,” IEEE conference, Lasers and Electro-Optics, 1999. CLEO/Pacific Rim '99. The Pacific Rim Conference on Vol. 2
Chapter 3.
[1] S. Nakamura and M. Senoh, ”Superbright green InGaN single-quantum-well-structure light-emitting diodes”, Jpn. J. Appl. Phys. Lett., Vol.34, L1332-L1335, 1995.
[2] S. J. Chang, W. C. Lai, Y. K. Su, J. F. Chen, C. H. Liu and U. H. Liaw, "InGaN/GaN multiquantum well blue and green light emitting diodes", IEEE J. Sel. Top. Quan. Electron., Vol. 8, pp. 278-283, 2002.
[3] S. M. Myers, A. F. Wright, G. A. Petersen, W. R. Wampler, C. H. Seager, M. H. Crawford and J. Han, “Diffusion, release, and uptake of hydrogen in magnesium-doped gallium nitride: Theory and experiment”, J. Appl. Phys., Vol. 89, pp. 3195-3202, 2001.
[4] S. J. Chang, C. S. Chang, Y. K. Su, R. W. Chuang, Y. C. Lin, S. C. Shei, H. M. Lo, H. Y. Lin and J. C. Ke, "Highly reliable nitride based LEDs with SPS+ITO upper contacts", IEEE J. Quan. Electron., Vol. 39, pp. 1439-1443, 2003
[5] X. Guo and E. F. Schubert, “Crowding in GaN/InGaN light emitting diodes on insulating substrates”, J. Appl. Phys., Vol. 90, pp. 4191-4195, 2001.
[6] J. C. Chen, G. J. Sheu, F. S. Hwu, H. I. Chen, J. K. Sheu, T. X. Lee and C. C. Sun, “Electrical-optical analysis of a GaN/sapphire LED chip by considering the resistivity of the current-spreading layer”, Opt. Rev., Vol. 16, pp. 213-215, 2009.
[7] S. J. Chang, C. H. Kuo, Y. K. Su, L. W. Wu, J. K. Sheu, T. C. Wen, W. C. Lai, J. F. Chen and J. M. Tsai, "400nm InGaN/GaN and InGaN/AlGaN multiquantum well light-emitting diodes", IEEE J. Sel. Top. Quan. Electron., Vol. 8, pp. 744-748, 2002.
[8] C. S. Chang, S. J. Chang, Y. K. Su, C. T. Lee, Y. C. Lin, W. C. Lai, S. C. Shei, J. C. Ke and H. M. Lo, "Nitride-based LEDs with textured side walls", IEEE Photon. Technol. Lett., Vol. 16, pp. 750-752, 2004.
[9] R. A. Serway, Principles of Physics (2nd ed ed.). Fort Worth, Texas; London: Saunders College Pub. p. 602, 1998.
Chapter 4.
[1] S. Nakamura, M. Senoh, N. Iwasa, and S. Nagahama, “High-power InGaN single-quantum-well-structure blue and violet light-emitting diodes,” Appl. Phys. Lett., vol. 67, pp. 1868–1870, 1995.
[2] S. J. Chang,W.C. Lai,Y.K. Su, J. F. Chen,C.H. Liu, and U. H. Liaw,“InGaN/GaNmultiquantumwell blue and green light emitting diodes,” IEEE J. Sel. Top. Quantum Electron., vol. 8, no. 2, pp. 278–283, Mar.–April 2002.
[3] Y. J. Lee, J. M. Hwang, T. C. Hsu, M. H. Hsieh, M. J. Jou, B. J. Lee, T. C. Lu, H. C. Kuo, and S. C.Wang, “Enhancing the output power of GaN-based LEDs grown on wet-etched patterned sapphire substrates,” IEEE Photon. Technol. Lett., vol. 18, no. 12, pp. 1152–1154, Dec. 2006.
[4] S. J.Chang,C.H.Kuo,Y.K. Su, L. W.Wu, J.K. Sheu, T. C. Wen, W. C. Lai, J. F. Chen, and J. M. Tsai, “400 nm InGaN/GaN and InGaN/ AlGaN multiquantum well light-emitting diodes,” IEEE J. Sel. Top. Quantum Electron., vol. 8, no. 3, pp. 744–748, May–Jun. 2002.
[5] S. J. Chang, L. W. Wu, Y. K. Su, Y. P. Hsu, W. C. Lai, J. M. Tsai, J. K. Sheu, and C. T. Lee, “Nitride-based LEDs with 800 –grown p-AlInGaN/GaN double cap layers,” IEEE Photon. Technol. Lett., vol. 16, no. 12, pp. 1447–1449, Dec. 2004.
[6] T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamurra,“Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett., vol. 84, pp. 855–857, 2004.
[7] A. David, “Surface-roughened light-emitting diodes: An accurate model,” J. Display Technol., vol. 9, pp. 301–316, 2013.
[8] D. F. Feezell, J. S. Speck, S. P. DenBaars, and S. Nakamura, “Semipolar (2 0 2 ̅ 1 ̅) InGaN/GaN light-emitting diodes for high-efficiency solid-state lighting,” J. Display Technol., vol. 9, pp. 190–198, 2013.
[9] H. Zhao, G. Y. Liu, J. Zhang, J. D. Poplawsky, V. Dierolf, andN. Tansu,b“Approaches for high internal quantum efficiency green InGaN lightemitting diodes with large overlap quantum wells,” Opt. Exp., vol. 19,pp. A991–A1007, 2011.
[10] R. A. Arif, H. Zhao, Y. K. Ee, and N. Tansu, “Spontaneous emission and characteristics of staggered InGaN quantum wells light emitting diodes,” IEEE J. Quantum Electron., vol. 44, no. 3, pp. 573–580, Mar. 2008.
[11] C. K. Wang, T. H. Chiang, K. Y. Chen, Y. Z. Chiou, T. K. Lin, S. P. Chang, and S. J. Chang, “Investigating the effect of piezoelectric polarization on GaN-based LEDs with different quantum barrier thickness,” Display Technol., vol. 9, pp. 207–212, 2013.
[12] S. Choi, M. H. Ji, J.M. Kim,M.M. Satter, P. D. Yoder, J. H. Ryou, R. D. Dupuis, A. M. Fischer, and F. A. Ponce, “Efficiency droop due to electron spill-over and limited hole injection in III-nitride visible lightemitting diodes employing lattice-matched InAlN electron blocking layers,” Appl. Phys. Lett., vol. 101, 2012, Art. ID 161110.
[13] G. Y. Liu, J. Zhang, C. K. Tan, and N. Tansu, “Using large-bandgap AlGaInN thin barrier layers in InGaN quantum-well light-emitting diodes,” IEEE Photon. J., vol. 5, 2013, Art. ID 2201011.
[14] S. C. Hsu, C. Y. Lee, J. M. Hwang, J. Y. Su, D. S. Wuu, and R. H. Horng, “Enhanced light output in roughened GaN-based light emitting diodes using electrodeless photochemical etching,” IEEE Photon. Technol. Lett., vol. 18, no. 12, pp. 2472–2474, Dec. 2006.
[15] C. H. Chiu, M. H. Lo, T. C. Lu, P. C. Yu, H. W. Huang, H. C. Kuo, and S. C. Wang, “Nano-processing techniques applied in GaN-base light-emitting devices with self-assembly Ni nano-masks,” J. Lightw Technol., vol. 26, no. 7, pp. 1445–1454, Jul. 2008.
[16] J. T. Chen, W. C. Lai, Y. C. Chang, J. K. Sheu, and W. C. Sen, “GaNbased light emitting diodes with micro- and nano-patterned structures by femtosecond laser nonlinear decomposition,” Appl. Phys. Lett., vol. 101, 2012, Art. ID 131103.
[17] Y. K. Ee, P. Kumnorkaew, R. A. Arif, H. Tong, H. P. Zhao, J. F. Gilchrist, and N. Tansu, “Optimization of light extraction efficiency of III-nitride LEDs with self-assembled colloidal-based microlenses,” IEEE J. Sel. Topic Quantum Electron., vol. 15, no. 4, pp. 1218–1225, Jul.–Aug. 2009.
[18] Y. K. Ee, P. Kumnorkaew, R. A. Arif, H. Tong, J. F. Gilchrist, and N. Tansu, “Light extraction efficiency enhancement of InGaN quantum wells light-emitting diodes with polydimethylsiloxane concave microstructures,” Opt. Exp., vol. 17, pp. 13747–13757, 2009.
[19] P. F. Zhu, G. Y. Liu, J. Zhang, andN. Tansu, “FDTD analysis on extraction efficiency of GaN light-emitting diodes with microsphere arrays,” J. Display Technol., vol. 9, pp. 317–323, 2013.
[20] X. H. Li, P. F. Zhu, G. Y. Liu, J. Zhang, R. B. Song, Y. K. Ee, P. Kumnorkaew, J. F. Gilchrist, andN. Tansu, “Light extraction efficiency enhancement of III-nitride light-emitting diodes by using 2-D close packed TiO2 microsphere arrays,” J. Display Technol., vol. 9, pp. 324–332, 2013.
[21] J. Jewell, D. Simeonov, S. C. Huang, Y. L. Hu, S. Nakamura, J. Speck, and C. Weisbuch, “Double embedded photonic crystals for extraction of guided light in light-emitting diodes,” Appl. Phys. Lett., vol. 100, 2012, Art. ID 171105.
[22] J. J. Wierer, Jr, A. David, and M. M. Megens, “III-nitride photoniccrystal light-emitting diodes with high extraction efficiency,” Nature Photon., vol. 3, pp. 163–169, 2009.
[23] C. H. Liu, R. W. Chuang, S. J. Chang, Y. K. Su, L. W. Wu, and C. C. Lin, “Improved light output power of InGaN/GaN MQW LEDs by lower temperature p-GaN rough surface,” Mater. Sci. Eng. B, vol. 112, pp. 10–13, 2004.
[24] C. M. Tsai, J. K. Sheu, W. C. Lai, Y. P. Hsu, P. T. Wang, C. T. Kuo, C. W. Kuo, S. J. Chang, and Y. K. Su, “ Enhanced output power in GaN-based LEDs with naturally textured surface grown by MOCVD,” IEEE Electron Device Lett., vol. 26, pp. 464–466, 2005.
[25] Y. P. Hsu, S. J. Chang, Y.K. Su, S. C. Chen, J.M. Tsai, W.C. Lai, C. H Kuo, and C. S. Chang, “InGaN-GaN MQW LEDs with Si treatment, IEEE Photon. Technol. Lett., vol. 17, no. 10, pp. 1620–1622, Oct. 2005.
[26] S. J. Chang, C. H. Chen, P. C. Chang, Y. K. Su, P. C. Chen, Y. D. Jhou, H. Hung, C. M. Wang, and B. R. Huang, “Nitride-based LEDs with p-InGaN capping layer,” IEEE Trans. Electron Devices, vol. 50, no. 12, pp. 2567–2570, Dec. 2003.
[27] C. H. Jang, J. K. Sheu, C. M. Tsai, S. J. Chang, W. C. Lai, M. L. Lee, T. K. Ko, C. F. Shen, and S. C. Shei, “Improved performance of GaN-based blue LEDs with the InGaN insertion layer between the MQW active layer and the n-GaN cladding layer,” IEEE J. Quantum Electron., vol. 46, no. 3, pp. 513–517, Mar. 2010.
[28] L.W. Wu, S. J. Chang, T. C. Wen, Y.K. Su, W.C. Lai, C.H. Kuo, C.H. Chen, and J. K. Sheu, “Influence of Si-doping on the characteristics of InGaN/GaN multiple quantum well blue light emitting diodes,” IEEE Quantum Electron., vol. 38, no. 3, pp. 446–450, Mar. 2002.
[29] S. J. Chang, C. S. Chang, Y. K. Su, R. W. Chuang, Y. C. Lin, S. C. Shei, H. M. Lo, H. Y. Lin, and J. C. Ke, “Highly reliable nitride base LEDs with SPS+ITO upper contacts,” IEEE J. Quantum Electron., vol. 39, no. 6, pp. 1439–1443, Jun. 2003.
[30] S. C. Shei, W. C. Lai, J. K. Sheu, I. H. Hung, and S. J. Chang, “The output power enhancements of GaN-based blue light-emitting diodes with highly reflective Ag/Cr/Au trilayer omnidirectional reflective electrode pads,” Jpn. J. Appl. Phys., vol. 48, 2009, Art. ID 102103.
Chapter 5.
[1] S. Nakamura, M. Senoh, N. Iwasa, and S. Nagahama, “High-power InGaN single-quantum-well-structure blue and violet light-emitting diodes,” Appl. Phys. Lett., vol. 67, pp. 1868–1870, 1995.
[2] C. T. Lee, U. Z. Yang, C. S. Lee, and P. S. Chen, “White light emission of monolithic carbon-implanted InGaN-GaN light-emitting diodes,” IEEE Photon. Technol. Lett., vol. 18, pp. 2029–2031, 2006.
[3] S. H. Han et al., “Effect of electron blocking layer on efficiency droop in InGaN/GaN multiple quantum well light-emitting diodes,” Appl. Phys. Lett., vol. 94, Art. no. 231123, 2009.
[4] H. Kim et al., “Design of high-efficiency GaN-based light emitting diodes with vertical injection geometry,” Appl. Phys. Lett., vol. 91, Art. no. 023510, 2007.
[5] K. Tadatomo et al., “High output power InGaN ultraviolet light-emitting diodes fabricated on patterned substrates using metalorganic vapor phase epitaxy,” Jpn. J. Appl. Phys., vol. 40, pt. 2, pp. L583–L585, 2001.
[6] J. J. Wierer et al., “High-power AlGaInN flip-chip light-emitting diodes,” Appl. Phys. Lett., vol. 78, pp. 3379–3381, 2001.
[7] C. C. Lin and C. T. Lee, “Enhanced light extraction mechanism of GaN-based light-emitting diodes using top surface and side-wall nanorod arrays,” IEEE Photon. Technol. Lett., vol. 22, pp. 1132–1134, 2010.
[8] M. Koike, N. Shibata, H. Kato, and Y. Takahashi, “Development of high efficiency GaN-based multiquantum-well light-emitting diodes and their applications,” IEEE J. Sel. Topics Quantum Electron., vol. 8, pp. 271–277, 2002.
[9] T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamurra,“Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett., vol. 84, pp. 855–857, 2004.
[10] L. W. Wu et al., “In0.23Ga0.77N/GaN MQW LEDs with a low temperature GaN cap layer,” Solid-State Electron., vol. 47, pp. 2027–2030, 2003.
[11] C. S. Chang et al., “Nitride-based LEDs with textured side-walls,” IEEE Photon. Technol. Lett., vol. 16, pp. 750–752, 2004.
[12] C. C. Kao et al., “Light-output enhancement in a nitride-based light-emitting diode with 22 undercut sidewalls,” IEEE Photon. Technol. Lett., vol. 17, pp. 19–21, 2005.
[13] C. E. Lee et al., “Luminance enhancement of flip-chip light-emitting diodes by geometric sapphire shaping structure,” IEEE Photon. Technol.. Lett., vol. 20, pp. 184–186, 2008.
[14] K. C. Chen, Y. K. Su, C. L. Lin, and H. C. Hsu, “Laser scribing of sapphire substrate to increase side light extraction of GaN-based light emitting diodes,” J. Lightw. Technol., vol. 29, pp. 1907–1912, 2011.
[15] Y. Y. Zhang et al., “Light extraction efficiency improvement by multiple laser stealth dicing in InGaN-based blue light-emitting diodes,” Optical Express, vol. 20, pp. 6808–6815, 2012.
[16] S. J. Chang et al., “Nitride-based LEDs with p-InGaN capping layer,” IEEE Trans. Electron Devices, vol. 50, pp. 2567–2570, Dec. 2003.
[17] L. W. Wu et al., “Influence of Si-doping on the characteristics of InGaN/GaN multiple quantum well blue light emitting diodes,” IEEE Trans. Electron Devices, vol. 38, no. 3, pp. 446–450, Mar. 2002.
[18] C. M. Tsai et al., “Enhanced output power in GaN-based LEDs with naturally textured surface grown by MOCVD,” IEEE Electron Devices Lett., vol. 26, pp. 464–466, 2005.
[19] S. J. Chang et al., “Highly reliable nitride based LEDs with SPS＋ITO upper contacts,” IEEE J. Quantum Electron., vol. 39, pp. 1439–1443, 2003.
[20] J. H. Lee, N. S. Kim, D. Y. Lee, and J. H. Lee, “Effect of residual stress and sidewall emission of InGaN-based LED by varying sapphire substrate thickness,” IEEE Photon. Technol. Lett., vol. 21, pp. 1151–1153, 2009.
Chapter 6.
[1] Y. J. Lee, J. M. Hwang, T. C. Hsu, M. H. Hsieh, M. J. Jou, B. J. Lee, T. C. Lu, H. C. Kuo, and S. C.Wang, “Enhancing the output power of GaN-based LEDs grown on wet-etched patterned sapphire substrates,” IEEE Photon. Technol. Lett., vol. 18, no. 12, pp. 1152–1154, Dec. 2006.
[2] S. J.Chang,C.H.Kuo,Y.K. Su, L. W.Wu, J.K. Sheu, T. C. Wen, W. C. Lai, J. F. Chen, and J. M. Tsai, “400 nm InGaN/GaN and InGaN/ AlGaN multiquantum well light-emitting diodes,” IEEE J. Sel. Top. Quantum Electron., vol. 8, no. 3, pp. 744–748, May–Jun. 2002.
[3] S. J. Chang, L. W. Wu, Y. K. Su, Y. P. Hsu, W. C. Lai, J. M. Tsai, J. K. Sheu, and C. T. Lee, “Nitride-based LEDs with 800 –grown p-AlInGaN/GaN double cap layers,” IEEE Photon. Technol. Lett., vol. 16, no. 12, pp. 1447–1449, Dec. 2004.
[4] T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamurra, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett., vol. 84, pp. 855–857, 2004.
[5] A. David, “Surface-roughened light-emitting diodes: An accurate model,” J. Display Technol., vol. 9, pp. 301–316, 2013.
[6] M. R. Krames, M. Ochiai-Holcomb, G. E. Höfler, C. Carter-Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1-x)0.5In0.5P/GaP light-emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett., vol. 75, pp. 2365–2367, 1999.
[7] J. Baur, B. Hahn, M. Fehrer, D. Eisert, W. Stein, A. Plössl, F. Kühn, H. Zull, M. Winter, and V. Härle, “InGaN on SiC LEDs for high flux and high current applications,” Physica Status Solidi A, vol. 194, pp. 399–402, 2002.
[8] C. S. Chang, S. J. Chang, Y. K. Su, C. T. Lee, Y. C. Lin, W. C. Lai, S. C. Shei, J. C. Ke, and H. M. Lo, “Nitride-based LEDs with textured side-walls,” IEEE Photon. Technol. Lett., vol. 16, no. 3, pp. 750–752, Mar. 2004.
[9] C. F. Lin, Z. J. Yang, B. H. Chin, J. H. Zheng, J. J. Dai, B. C. Shieh, and C. C. Chang, “Enhanced light output power in InGaN light-emitting diodes by fabricating inclined undercut structure,” J. Electrochem. Soc., vol. 153, pp. G1020–G1024, 2006.
[10] K. C. Chen, Y. K. Su, C.-L. Lin, and H. C. Hsu, “Laser scribing of sapphire substrate to increase side light extraction of GaN-based light emitting diodes,” J. Lightwave Technol. 29(13), 1907–1912 (2011).
[11] Eun-Hyun Park, Jin Jang, Shalini Gupta, Ian Ferguson, Cheol-Hoi Kim, Soo-Kun Jeon and Joong-Seo Park, “Air-voids embedded high efficiency InGaN-light emitting diode,” Appl. Phys. Lett., vol. 93, pp. 191103, 2008.
[12] W. C. Lai, Y. Y. Yang, L. C. Peng, S. W. Yang, Y. R. Lin and J. K. Sheu, “GaN-based light emitting diodes with embedded SiO2 pillars and air gap array structures,” Appl. Phys. Lett., vol. 97, pp. 081103, 2010.
[13] J. K. Sheu, S. J. Tu, Y. H. Yeh, M. L. Lee and W. C. Lai, “Gallium nitride-based light-emitting diodes with embedded air voids grown on Ar-implanted AlN/sapphire substrate,” Appl. Phys. Lett., vol. 101, pp. 151103, 2012.
[14] J. Z. Liu, Martin D. B. Charlton, C. H. Lin, K. Y. Lee, Chirenjeevi Krishnan, M. C. Wu, “Efficiency Improvement of Blue LEDs Using a GaN Burried Air Void Photonic Crystal With High Air Filling Fraction,” IEEE J. Quantum Electron., vol. 50, no. 5, pp. 314–320, Mar. 2014.
[15] S. J. Chang, L. M. Chang, J. Y. Chen, C. S. Hsu, D. S. Kuo, C. F. Shen, W. S. Chen, T. K. Ko, “GaN-Based Light-Emitting Diodes Prepared With Shifted Laser Stealth Dicing,” IEEE J. Display Technol., vol. 12, pp. 195, 2016.
[16] C. H. Jang, J. K. Sheu, C. M. Tsai, S. J. Chang, W. C. Lai, M. L. Lee, T. K. Ko, C. F. Shen, and S. C. Shei, “Improved performance of GaN-based blue LEDs with the InGaN insertion layer between the MQW active layer and the n-GaN cladding layer,” IEEE J. Quantum Electron., vol. 46, no. 3, pp. 513–517, Mar. 2010.
[17] L.W. Wu, S. J.Chang, T. C. Wen, Y.K. Su, W.C. Lai, C.H. Kuo, C.H. Chen, and J. K. Sheu, “Influence of Si-doping on the characteristics of InGaN/GaN multiple quantum well blue light emitting diodes,” IEEE J. Quantum Electron., vol. 38, no. 3, pp. 446–450, Mar. 2002.
[18] C. M. Tsai, J. K. Sheu, W. C. Lai, Y. P. Hsu, P. T. Wang, C. T. Kuo, C. W. Kuo, S. J. Chang, and Y. K. Su, “ Enhanced output power in GaN-based LEDs with naturally textured surface grown by MOCVD,” IEEE Electron Device Lett., vol. 26, pp. 464–466, 2005.
[19] S. J. Chang, C. S. Chang, Y. K. Su, R. W. Chuang, Y. C. Lin, S. C. Shei, H. M. Lo, H. Y. Lin, and J. C. Ke, “Highly reliable nitride based LEDs with SPS+ITO upper contacts,” IEEE J. Quantum Electron., vol. 39, no. 6, pp. 1439–1443, Jun. 2003.
Chapter 7.
[1] K. J. Chen, H. T. Kuo, Y. C. Chiang, H. C. Chen, C. H. Wang, M. H. Shin, C. C. Lin, C. J. Pan, and H. C. Kuo, “Efficiency and droop improvement in hybrid warm white LEDs using InGaN and AlGaInP high-voltage LEDs,” IEEE/OSA Journal of Display Technology, vol. 9, no. 4, pp. 280–284, 2013.
[2] K. J. Chen, H. T. Kuo, H. C. Chen, M. H. Shih, C. H. Wang, S. H. Chien, S. H. Chiu, C. C. Lin, C. J. Pan, and H. C. Kuo, “High thermal stability of correlated color temperature using current compensation in hybrid warm white high-voltage LEDs,” Optics Express, vol. 21, article S2, pp. A201–A207, 2013.
[3] C. H. Wang, D. W. Lin, C. Y. Lee, M. A. Tsai, G. L. Chen, H. T. Kuo, W. H. Hsu, H. C. Kuo, T. C. Lu, S, C, Wag, and G. C. Chi, “Efficiency and droop improvement in GaN-based high-voltage light-emitting diodes,” IEEE Electron Device Letters, vol. 32, no. 8, pp. 1098–1100, 2011.