在本論文中，為了改善氮化鎵/氮化銦鎵系(GaN/InGaN)發光二極體之光萃取效率(light extraction efficiency)，吾人研製一系列具有短深度微米孔洞陣列及特殊圖案化邊牆之複合結構式高品質氮化鎵/氮化銦鎵系發光二極體。以此複合結構為主軸，進一步提出奈米材料應用及元件製程技術，其中包含利用快速對流沉積法(rapid convection deposition, RCD)製備混合式二氧化矽微奈米球抗反射保護層以及利用快速對流沉積法形成嵌入二氧化矽奈米球單層結構來形成反射鏡結構，有效提升氮化鎵系發光二極體之光電轉換效率(wall-plug efficiency, WPE)。本研究對複合結構式氮化鎵/氮化銦鎵系發光二極體之光電特性，及各種特定結構之製備方式皆有深入且詳細的研究及探討。
首先，吾人利用感應耦合電漿離子(inductively coupled plasma, ICP)蝕刻製程，製備出具有不同深度微米孔洞陣列及特殊邊牆結構之氮化鎵/氮化銦鎵系發光二極體，短深度微米孔洞陣列可在不影響電性特性之下，目的保留多重量子井(MQW)，有效增加發光面積且降低在氮化鎵/空氣介面之內部全反射(total internal reflection, TIR)，並增加光子散射(photons scattering)至元件外部的機會。另外，經由快速對流沉積法，塗佈混合式二氧化矽微奈米球抗反射保護層之氮化鎵/氮化銦鎵系發光二極體。在不影響順向電性特性下，有效抑制元件之逆向漏電流，並進一步提升元件表面粗糙度，使得光子有足夠的機會被導引至光逃離錐角(photon escape cones)，降低內部全反射效應。此外，二氧化矽保護層同時具備抗反射性質，抑制元件內部產生之Fresnel光損失(Fresnel loss)。相較於傳統平面式氮化鎵系發光二極體，在光輸出功率(light output power)、光通量(luminous flux)、光電轉換效率(wall-plug efficiency)及外部量子效率(external quantum efficiency)分別提升51.3%、 53.59%、54.55%及52.08%。
其次，為了有效改善高效率發光二極體之光萃取效率，吾人提出利用由快速對流沉積法嵌入二氧化矽奈米球單層結構來形成背鍍反射鏡結構，首先將具有自組裝偽六腳緊密堆積(pseudo-hexagonal close packing)陣列之奈米球單層結構塗佈在元件底部藍寶石基板，並蒸鍍鋁金屬反射鏡(aluminum metal mirror)，利用奈米球之圓球外型形成背鍍反射鏡，此結構改變反射光之光路徑可降低內部全反射(total internal reflection, TIR)；除此之外，由於奈米球單層結構於球與球之間會形成空氣孔洞(air voids) 陣列，利用空氣孔洞陣列導致減少元件底部之光吸收，有效地提升光子逃離錐角散射至元件外，且利用短深度微米孔洞陣列、特殊邊牆結構及二氧化矽保護層混合結構，此修飾結構大幅地改善光萃取效率。相較於傳統平面式氮化鎵/氮化銦鎵系發光二極體，在光輸出功率(light output power)、光通量(luminous flux)、光電轉換效率(wall-plug efficiency)及外部量子效率(external quantum efficiency)分別提升57.8%、47.2%、58.6%及58.1%。
最後，延續前章探討經由快速對流沉積法，塗佈不同尺寸二氧化矽抗反射保護層於具有短深度微米孔洞陣列及特殊邊牆結構之氮化鎵/氮化銦鎵系發光二極體。在不影響順向電性特性下，有效抑制元件之逆向漏電流，並改變元件表面粗糙度，不同表面粗糙度使得光子被導引至光逃離錐角(photon escape cones) 的機會不同。此外，二氧化矽保護層同時具備抗反射性質，抑制元件內部產生之Fresnel光損失(Fresnel loss)。相較於傳統平面式氮化鎵/氮化銦鎵系發光二極體，在光輸出功率、光通量、光電轉換效率及外部量子效率分別提升61.2%、39.9%、61.2%及62.0%。本研究論文中所研製之高品質氮化鎵/氮化銦鎵系發光二極體，皆有效提升光電轉換效率，在商業應用上相當具有潛力。

In this thesis, in order to enhance light extraction efficiency (LEE), GaN/InGaN-based light-emitting diodes (LEDs) with specific sidewalls are fabricated and studied. The device fabrication process and nanomaterials applications, including a shallower depth of a microhole array, textured sidewalls, nanospheres (NSs) backside reflector via rapid convection deposition (RCD), and an appropriate SiO2 passivation layer via a RCD approach are proposed to further improve wall-plug efficiency (WPE) of the studied devices. The optical and electrical properties of these multi-structured GaN/InGaN-based LEDs are studied and discussed in detail. In addition, the related fabrication processes of these specific structures are also explained in detail.
A hybrid structure, including 45° sidewalls, a microhole array, and an SiO2 nanoparticle (NP)/microsphere (MS) passivation layer, is used to produce GaN/InGaN-based light-emitting diodes (LEDs). The influences of the microhole depth and SiO2 NP/MS passivation layer on the LED performance are studied. A shallower depth (0.25 µm) of a microhole array shows better optical properties due to the complete preservation of the GaN/InGaN multiple quantum well (MQW) region. In addition, the use of a thin SiO2 NP/MS passivation layer gives a remarkably reduced reverse-biased leakage current and improved optical performance. Experimentally, under an injection current of 400 mA, the studied device, with a proper hybrid structure, shows enhancements of 51.3%, 53.59%, 54.55%, and 52.08% in light output power (LOP), luminous flux, wall-plug efficiency, and external quantum efficiency (EQE), respectively, as compared to a conventional LED device. These improvements are mainly caused by the reduced total internal reflection and Fresnel reflection which increase scattering probability and the opportunity to find photon escape cones. So, the studied hybrid structure in this work is a promising route to fabricate high-performance GaN/InGaN-based LEDs.
An approach to improve light extraction efficiency of high power GaN/InGaN-based LEDs by use of the nanospheres backside reflector is studied. A backside reflector is taken shape by depositing a self-assembled SiO2 nanosprere monolayer via a RCD approach between Al metal mirror and backside of sapphire substrate. Due to the use of inserting SiO2 nanospheres, hemispherical patterns could be transferred to the deposited reflector. However, photons could be redirected into arbitrary angles for light extraction by the transferred concave surface. In addition, the air void is formed due to the presence of gap between SiO2 nanospheres. It could effectively improve light scattering effect. Hence, a hybrid structure, including backside reflector, 45° sidewalls, a microhole array, and an SiO2 nanoparticle (NP)/microsphere (MS) passivation layer, is used to produce GaN/InGaN-based light-emitting diodes (LEDs). This assuredly gives photons more opportunities to find the escape cone. Experimentally, as compared to a conventional LED device under an injection current of 400 mA, the studied device, with a proper hybrid structure, shows enhancements of 57.8%, 47.2%, 58.6%, and 58.1% in light output power (LOP), luminous flux, wall-plug efficiency, and external quantum efficiency (EQE), respectively, Therefore, these results reveal that use of the proper hybrid structure could effectively improve the optical performance of high-performance GaN/InGaN-based LED applications.
Finally, the characteristics of GaN/InGaN-based light emitting diodes (LEDs) with a hybrid structure, including a shallower depth of a microhole array, 45° sidewalls, and an appropriate SiO2 passivation layer, were fabricated and studied. The use of the different size of passivation layer, formed via RCD method, causes an effective reduction in reverse-biased leakage current. The employment of the different size of SiO2 with a smaller size (30 nm) yields improved optical properties due to the highest roughened surface. In addition, the employment of hybrid structures of SiO2 NP/MS passivation layer improved optical properties due to increase surface roughness. Experimentally, as compared to a conventional LED device under an injection current of 400 mA, the studied device, with a proper hybrid structure, shows enhancements of 61.2%, 39.9%, 62.0%, and 61.2% in light output power (LOP), luminous flux, wall-plug efficiency, and external quantum efficiency (EQE), respectively, Therefore, these results reveal that use of the proper hybrid structure could effectively improve the optical performance of high-performance GaN/InGaN-based LED applications.
These proposed hybrid specific structures, which were employed in GaN/InGaN-based LED, indeed improve the total light output performance and reduce the power consumption. Therefore, the high-performance GaN/InGaN-based LEDs possesses commercial potential to compete with traditional light sources for practical applications in solid-state lighting.

[1] M.R. Krames, O.B. Shchekin, R. Mueller-Mach, G.O. Mueller, L. Zhou, G. Harbers, and M.G. Craford, "Status and future of high-power light-emitting diodes for solid-state lighting," Journal of display technology, vol. 3, pp. 160-175, 2007.
[2] M.H. Crawford, "LEDs for solid-state lighting: performance challenges and recent advances," IEEE Journal of Selected Topics in Quantum Electronics, vol. 15, pp. 1028-1040, 2009.
[3] D.A. Steigerwald, J.C. Bhat, D. Collins, R.M. Fletcher, M.O. Holcomb, M.J. Ludowise, P.S. Martin, and S.L. Rudaz, "Illumination with solid state lighting technology," IEEE journal of selected topics in quantum electronics, vol. 8, pp. 310-320, 2002.
[4] H.á. Maruska, and J. Tietjen, "The preparation and properties of vapor‐deposited single‐crystal‐line GaN," Applied Physics Letters, vol. 15, pp. 327-329, 1969.
[5] H. Maruska, D. Stevenson, and J. Pankove, "Violet luminescence of Mg‐doped GaN," Applied Physics Letters, vol. 22, pp. 303-305, 1973.
[6] M. Ilegems, and R. Dingle, "Luminescence of Be‐and Mg‐doped GaN," Journal of Applied Physics, vol. 44, pp. 4234-4235, 1973.
[7] H. Maruska, and D. Stevenson, "Mechanism of light production in metal-insulator-semiconductor diodes; GaN: Mg violet light-emitting diodes," Solid-State Electronics, vol. 17, pp. 1171-1179, 1974.
[8] S. Yoshida, S. Misawa, and S. Gonda, "Improvements on the electrical and luminescent properties of reactive molecular beam epitaxially grown GaN films by using AlN‐coated sapphire substrates," Applied Physics Letters, vol. 42, pp. 427-429, 1983.
[9] H. Amano, N. Sawaki, I. Akasaki, and Y. Toyoda, "Metalorganic vapor phase epitaxial growth of a high quality GaN film using an AlN buffer layer," Applied Physics Letters, vol. 48, pp. 353-355, 1986.
[10] S. Nakamura, "GaN growth using GaN buffer layer," Japanese Journal of Applied Physics, vol. 30, pp. L1705, 1991.
[11] S. Nakamura, T. Mukai, and M. Senoh, "In situ monitoring and Hall measurements of GaN grown with GaN buffer layers," Journal of applied physics, vol. 71, pp. 5543-5549, 1992.
[12] H. Amano, M. Kito, K. Hiramatsu, and I. Akasaki, "P-type conduction in Mg-doped GaN treated with low-energy electron beam irradiation (LEEBI)," Japanese Journal of Applied Physics, vol. 28, pp. L2112, 1989.
[13] S. Nakamura, T. Mukai, M. Senoh, and N. Iwasa, "Thermal annealing effects on p-type Mg-doped GaN films," Japanese Journal of Applied Physics, vol. 31, pp. L139, 1992.
[14] S. Nakamura, N. Iwasa, M. Senoh, and T. Mukai, "Hole compensation mechanism of p-type GaN films," Japanese Journal of Applied Physics, vol. 31, pp. 1258, 1992.
[15] J. Neugebauer, and C.G. Van de Walle, "Hydrogen in GaN: Novel aspects of a common impurity," Physical review letters, vol. 75, pp. 4452, 1995.
[16] J. Neugebauer, and C.G. Van de Walle, "Role of hydrogen in doping of GaN," Applied physics letters, vol. 68, pp. 1829-1831, 1996.
[17] J. Pankove, E. Miller, and J. Berkeyheiser, Electroluminescence in GaN, Luminescence of Crystals, Molecules, and Solutions, , pp. 426-430 Springer1973.
[18] S. Nakamura, T. Mukai, and M. Senoh, "High-power GaN pn junction blue-light-emitting diodes," Japanese Journal of Applied Physics, vol. 30, pp. L1998, 1991.
[19] S. Nakamura, M. Senoh, and T. Mukai, "P-GaN/N-InGaN/N-GaN double-heterostructure blue-light-emitting diodes," Japanese Journal of Applied Physics, vol. 32, pp. L8, 1993.
[20] S. Nakamura, T. Mukai, and M. Senoh, "Candela‐class high‐brightness InGaN/AlGaN double‐heterostructure blue‐light‐emitting diodes," Applied Physics Letters, vol. 64, pp. 1687-1689, 1994.
[21] N.S. Shinbun, ‘pn junction DH blue LEDs with a brightness of more than 1000 mcd were developed by Nichia Chemical Industries Ltd, Japanese newspaper press release1993.
[22] S. Nakamura, M. Senoh, N. Iwasa, and S.-i. Nagahama, "High-brightness InGaN blue, green and yellow light-emitting diodes with quantum well structures," Japanese journal of applied physics, vol. 34, pp. L797, 1995.
[23] N. Gardner, G. Müller, Y. Shen, G. Chen, S. Watanabe, W. Götz, and M. Krames, "Blue-emitting InGaN–GaN double-heterostructure light-emitting diodes reaching maximum quantum efficiency above 200 A∕ cm 2," Applied Physics Letters, vol. 91, pp. 243506, 2007.
[24] J.K. Park, C.H. Kim, S.H. Park, H.D. Park, and S.Y. Choi, "Application of strontium silicate yellow phosphor for white light-emitting diodes," Applied physics letters, vol. 84, pp. 1647-1649, 2004.
[25] J.K. Sheu, S.J. Chang, C. Kuo, Y.K. Su, L. Wu, Y.C. Lin, W.C. Lai, J. Tsai, G.C. Chi, and R. Wu, "White-light emission from near UV InGaN-GaN LED chip precoated with blue/green/red phosphors," IEEE Photonics Technology Letters, vol. 15, pp. 18-20, 2003.
[26] S. Nakamura, "Background Story of the Invention of Efficient InGaN Blue‐Light‐Emitting Diodes (Nobel Lecture)," Angewandte Chemie International Edition, vol. 54, pp. 7770-7788, 2015.
[27] S. Nakamura, "Nobel Lecture: Background story of the invention of efficient blue InGaN light emitting diodes," Reviews of Modern Physics, vol. 87, pp. 1139, 2015.
[28] A. Bakin, A. Behrends, A. Waag, H.-J. Lugauer, A. Laubsch, and K. Streubel, "ZnO-GaN hybrid heterostructures as potential cost-efficient LED technology," Proceedings of the IEEE, vol. 98, pp. 1281-1287, 2010.
[29] H. Zhang, J. Zhu, Z. Zhu, Y. Jin, Q. Li, and G. Jin, "Surface-plasmon-enhanced GaN-LED based on a multilayered M-shaped nano-grating," Optics express, vol. 21, pp. 13492-13501, 2013.
[30] K.K. Kim, S.D. Lee, H. Kim, J.C. Park, S.-N. Lee, Y. Park, S.J. Park, and S.W. Kim, "Enhanced light extraction efficiency of GaN-based light-emitting diodes with ZnO nanorod arrays grown using aqueous solution," Applied Physics Letters, vol. 94, pp. 071118, 2009.
[31] K. Orita, S. Tamura, T. Takizawa, T. Ueda, M. Yuri, S. Takigawa, and D. Ueda, "High-extraction-efficiency blue light-emitting diode using extended-pitch photonic crystal," Japanese journal of applied physics, vol. 43, pp. 5809, 2004.
[32] C. Kuo, R. Fletcher, T. Osentowski, M. Lardizabal, M. Craford, and V. Robbins, "High performance AlGaInP visible light‐emitting diodes," Applied Physics Letters, vol. 57, pp. 2937-2939, 1990.
[33] M.C. Schmidt, K.C. Kim, H. Sato, N. Fellows, H. Masui, S. Nakamura, S.P. DenBaars, and J.S. Speck, "High power and high external efficiency m-plane InGaN light emitting diodes," Japanese journal of applied physics, vol. 46, pp. L126, 2007.
[34] K. Akita, T. Kyono, Y. Yoshizumi, H. Kitabayashi, and K. Katayama, "Improvements of external quantum efficiency of InGaN-based blue light-emitting diodes at high current density using GaN substrates," Journal of applied physics, vol. 101, pp. 033104, 2007.
[35] T. Truong, L. Campos, E. Matioli, I. Meinel, C. Hawker, C. Weisbuch, and P. Petroff, "Light extraction from GaN-based light emitting diode structures with a noninvasive two-dimensional photonic crystal," Applied Physics Letters, vol. 94, pp. 023101, 2009.
[36] Q.C. Hsu, J.J. Hsiao, T.L. Ho, and C.D. Wu, "Fabrication of photonic crystal structures on flexible organic light-emitting diodes using nanoimprint," Microelectronic Engineering, vol. 91, pp. 178-184, 2012.
[37] J.J. Wierer Jr, A. David, and M.M. Megens, "III-nitride photonic-crystal light-emitting diodes with high extraction efficiency," Nature Photonics, vol. 3, pp. 163, 2009.
[38] D.H. Kim, C.O. Cho, Y.G. Roh, H. Jeon, Y.S. Park, J. Cho, J.S. Im, C. Sone, Y. Park, and W.J. Choi, "Enhanced light extraction from GaN-based light-emitting diodes with holographically generated two-dimensional photonic crystal patterns," Applied Physics Letters, vol. 87, pp. 203508, 2005.
[39] E. Matioli, and C. Weisbuch, "Impact of photonic crystals on LED light extraction efficiency: approaches and limits to vertical structure designs," Journal of Physics D: Applied Physics, vol. 43, pp. 354005, 2010.
[40] Q.-A. Ding, K. Li, F. Kong, J. Zhao, and Q. Yue, "Improving the vertical light extraction efficiency of GaN-based thin-film flip-chip LED with double embedded photonic crystals," IEEE Journal of Quantum Electronics, vol. 51, pp. 1-9, 2014.
[41] T. Fujii, Y. Gao, R. Sharma, E. Hu, S. DenBaars, and S. Nakamura, "Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening," Applied physics letters, vol. 84, pp. 855-857, 2004.
[42] H.-W. Huang, J. Chu, C. Kao, T. Hseuh, T. Lu, H. Kuo, S. Wang, and C. Yu, "Enhanced light output of an InGaN/GaN light emitting diode with a nano-roughened p-GaN surface," Nanotechnology, vol. 16, pp. 1844, 2005.
[43] M.Y. Ke, C.Y. Wang, L.Y. Chen, H.H. Chen, H.L. Chiang, Y.W. Cheng, M.Y. Hsieh, C.P. Chen, and J. Huang, "Application of nanosphere lithography to LED surface texturing and to the fabrication of nanorod LED arrays," IEEE Journal of Selected Topics in Quantum Electronics, vol. 15, pp. 1242-1249, 2009.
[44] M. Yamada, T. Mitani, Y. Narukawa, S. Shioji, I. Niki, S. Sonobe, K. Deguchi, M. Sano, and T. Mukai, "InGaN-based near-ultraviolet and blue-light-emitting diodes with high external quantum efficiency using a patterned sapphire substrate and a mesh electrode," Japanese Journal of Applied Physics, vol. 41, pp. L1431, 2002.
[45] J.H. Lee, J. Oh, Y. Kim, and J.H. Lee, "Stress reduction and enhanced extraction efficiency of GaN-based LED grown on cone-shape-patterned sapphire," IEEE Photonics Technology Letters, vol. 20, pp. 1563-1565, 2008.
[46] Q. Zhou, M. Xu, Q. Li, and H. Wang, "Improved efficiency of GaN-based green LED by a nano-micro complex patterned sapphire substrate," IEEE Photonics Technology Letters, vol. 29, pp. 983-986, 2017.
[47] C.C. Kao, H. Kuo, K. Yeh, J. Chu, W. Peng, H. Huang, T. Lu, and S. Wang, "Light–output enhancement of nano-roughened GaN laser lift-off light-emitting diodes formed by ICP dry etching," IEEE Photonics Technology Letters, vol. 19, pp. 849-851, 2007.
[48] H. Huang, C. Lin, C. Yu, K. Lee, B. Lee, H. Kuo, S. Kuo, K.-M. Leung, and S. Wang, "Investigation of GaN-based vertical-injection light-emitting diodes with GaN nano-cone structure by ICP etching," Materials Science and Engineering: B, vol. 151, pp. 205-209, 2008.
[49] T.H. Hsueh, J.K. Sheu, H. Huang, J. Chu, C. Kao, H.C. Kuo, and S. Wang, "Enhancement in light output of InGaN-based microhole array light-emitting diodes," IEEE photonics technology letters, vol. 17, pp. 1163-1165, 2005.
[50] H.W. Huang, H. Kuo, J. Chu, C. Lai, C. Kao, T. Lu, S. Wang, R. Tsai, C. Yu, and C. Lin, "Nitride-based LEDs with nano-scale textured sidewalls using natural lithography," Nanotechnology, vol. 17, pp. 2998, 2006.
[51] D. Kuo, S.J. Chang, T. Ko, C. Shen, S. Hon, and S. Hung, "Nitride-based LEDs with phosphoric acid etched undercut sidewalls," IEEE Photonics Technology Letters, vol. 21, pp. 510-512, 2009.
[52] H.-W. Huang, C. Lai, W. Wang, T. Lu, H. Kuo, S. Wang, R. Tsai, and C. Yu, "Efficiency enhancement of GaN-based power-chip LEDs with sidewall roughness by natural lithography," Electrochemical and solid-state letters, vol. 10, pp. H59-H62, 2007.
[53] C.C. Kao, H.C. Kuo, H.W. Huang, J.T. Chu, Y.C. Peng, Y.L. Hsieh, C. Luo, S.C. Wang, C.C. Yu, and C.F. Lin, "Light-output enhancement in a nitride-based light-emitting diode with 22 undercut sidewalls," IEEE Photonics Technology Letters, vol. 17, pp. 19-21, 2004.
[54] Z. Zhang, C. Geng, Z. Hao, T. Wei, and Q. Yan, "Recent advancement on micro-/nano-spherical lens photolithography based on monolayer colloidal crystals," Advances in colloid and interface science, vol. 228, pp. 105-122, 2016.
[55] Y.C. Chang, S.C. Lu, H.C. Chung, S.M. Wang, T.D. Tsai, and T.F. Guo, "High-throughput nanofabrication of infra-red and chiral metamaterials using nanospherical-lens lithography," Scientific reports, vol. 3, pp. 3339, 2013.
[56] C.H. Hou, S.Z. Tseng, C.H. Chan, T.J. Chen, H.T. Chien, F.L. Hsiao, H.K. Chiu, C.C. Lee, Y.L. Tsai, and C.-C. Chen, "Output power enhancement of light-emitting diodes via two-dimensional hole arrays generated by a monolayer of microspheres," Applied Physics Letters, vol. 95, pp. 133105, 2009.
[57] A. Heltzel, S. Theppakuttai, S. Chen, and J.R. Howell, "Surface plasmon-based nanopatterning assisted by gold nanospheres," Nanotechnology, vol. 19, pp. 025305, 2007.
[58] N. Blondiaux, E. Scolan, G. Franc, and R. Pugin, Manufacturing of superhydrophobic surfaces combining nanosphere lithography with replication techniques, IEEE International Conference on Nanotechnology, pp. 1-6, 2012.
[59] M. Lee, C. Ho, and C. Fan, "High light extraction efficiency of gallium nitride light emitting diode with silicon oxide hemispherical microlens," Applied Physics Letters, vol. 92, pp. 061103, 2008.
[60] Y.K. Ee, R.A. Arif, N. Tansu, P. Kumnorkaew, and J.F. Gilchrist, "Enhancement of light extraction efficiency of InGaN quantum wells light emitting diodes using SiO2polystyrene microlens arrays," Applied Physics Letters, vol. 91, pp. 221107, 2007.
[61] L.Y. Chen, Y.Y. Huang, C.H. Chang, Y.H. Sun, Y.W. Cheng, M.Y. Ke, C.P. Chen, and J. Huang, "High performance InGaN/GaN nanorod light emitting diode arrays fabricated by nanosphere lithography and chemical mechanical polishing processes," Optics express, vol. 18, pp. 7664-7669, 2010.
[62] M.A. Tsai, P. Yu, C. Chao, C. Chiu, H. Kuo, S. Lin, J. Huang, T. Lu, and S. Wang, "Efficiency enhancement and beam shaping of GaN–InGaN vertical-injection light-emitting diodes via high-aspect-ratio nanorod arrays," IEEE Photonics Technology Letters, vol. 21, pp. 257-259, 2009.
[63] H.K. Lee, Y.H. Ko, G.S.R. Raju, and J.S. Yu, "Light-extraction enhancement and directional emission control of GaN-based LEDs by self-assembled monolayer of silica spheres," Optics Express, vol. 20, pp. 25058-25063, 2012.
[64] Q. Zhang, K.H. Li, and H.W. Choi, "Polarized emission from InGaN light-emitting diodes with self-assembled nanosphere coatings," IEEE Photonics Technology Letters, vol. 24, pp. 1642-1645, 2012.
[65] C.H. Hsu, Y.C. Chan, W.C. Chen, C.H. Chang, J.K. Liou, S.Y. Cheng, D.F. Guo, and W.C. Liu, "Study of GaN-based LEDs with hybrid SiO2 microsphere/nanosphere antireflection coating as a passivation layer by a rapid convection deposition," IEEE Transactions on Electron Devices, vol. 64, pp. 1134-1139, 2017.
[66] Z.Z. Gu, A. Fujishima, and O. Sato, "Fabrication of high-quality opal films with controllable thickness," Chemistry of Materials, vol. 14, pp. 760-765, 2002.
[67] Y. Xia, B. Gates, Y. Yin, and Y. Lu, "Monodispersed colloidal spheres: old materials with new applications," Advanced Materials, vol. 12, pp. 693-713, 2000.
[68] D. Wang, and H. Möhwald, "Rapid fabrication of binary colloidal crystals by stepwise spin‐coating," Advanced Materials, vol. 16, pp. 244-247, 2004.
[69] F. García‐Santamaría, H.T. Miyazaki, A. Urquía, M. Ibisate, M. Belmonte, N. Shinya, F. Meseguer, and C. López, "Nanorobotic manipulation of microspheres for on‐chip diamond architectures," Advanced Materials, vol. 14, pp. 1144-1147, 2002.
[70] X.H. Li, P. Zhu, G. Liu, J. Zhang, R. Song, Y.K. Ee, P. Kumnorkaew, J.F. Gilchrist, and N. Tansu, "Light Extraction Efficiency Enhancement of III-Nitride Light-Emitting Diodes by Using 2-D Close-Packed TiO2 Microsphere Arrays," Journal of Display Technology, vol. 9, pp. 324-332, 2013.
[71] 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," Optics Express, vol. 17, pp. 13747-13757, 2009.
[72] P. Zhu, G. Liu, J. Zhang, and N. Tansu, "FDTD analysis on extraction efficiency of GaN light-emitting diodes with microsphere arrays," Journal of Display Technology, vol. 9, pp. 317-323, 2013.
[73] C.Y. Fang, Y.L. Liu, Y.C. Lee, H.L. Chen, D.H. Wan, and C.C. Yu, "Nanoparticle stacks with graded refractive indices enhance the omnidirectional light harvesting of solar cells and the light extraction of light‐emitting diodes," Advanced Functional Materials, vol. 23, pp. 1412-1421, 2013.
[74] D. Steigerwald, S. Rudaz, H. Liu, R.S. Kern, W. Götz, and R. Fletcher, "III–V nitride semiconductors for high-performance blue and green light-emitting devices," Jom, vol. 49, pp. 18-23, 1997.
[75] T. Mukai, M. Yamada, and S. Nakamura, "Characteristics of InGaN-based UV/blue/green/amber/red light-emitting diodes," Japanese Journal of Applied Physics, vol. 38, pp. 3976, 1999.
[76] M. Koike, N. Shibata, H. Kato, and Y. Takahashi, "Development of high efficiency GaN-based multiquantum-well light-emitting diodes and their applications," IEEE Journal of selected topics in quantum electronics, vol. 8, pp. 271-277, 2002.
[77] N.Y. Pacella, M.T. Bulsara, C. Drazek, E. Guiot, and E.A. Fitzgerald, "Fabrication and thermal budget considerations of advanced Ge and InP SOLES substrates," ECS Journal of Solid State Science and Technology, vol. 4, pp. P258-P264, 2015.
[78] J.K. Liou, C.C. Chen, P.C. Chou, S.Y. Cheng, J.H. Tsai, R.C. Liu, and W.C. Liu, "Effects of the Use of an Aluminum Reflecting and an SiO2 Insulating Layers (RIL) on the Performance of a GaN-Based Light-Emitting Diode With the Naturally Textured p-GaN Surface," IEEE Transactions on Electron Devices, vol. 60, pp. 2282-2289, 2013.
[79] C.L. Liao, Y.F. Chang, C.L. Ho, and M.C. Wu, "High-speed GaN-based blue light-emitting diodes with gallium-doped ZnO current spreading layer," IEEE Electron Device Letters, vol. 34, pp. 611-613, 2013.
[80] P. Mao, F. Sun, H. Yao, J. Chen, B. Zhao, B. Xie, M. Han, and G. Wang, "Extraction of light trapped due to total internal reflection using porous high refractive index nanoparticle films," Nanoscale, vol. 6, pp. 8177-8184, 2014.
[81] S. Huang, C. Chang, H. Lin, X. Li, Y. Lin, and C. Liu, "Fabrication of nano-cavity patterned sapphire substrate using self-assembly meshed Pt thin film on c-plane sapphire substrate," Thin Solid Films, vol. 628, pp. 127-131, 2017.
[82] C.T. Kuo, L.H. Hsu, B.H. Huang, H.C. Kuo, C.C. Lin, and Y.J. Cheng, "Influence of the microstructure geometry of patterned sapphire substrates on the light extraction efficiency of GaN LEDs," Applied optics, vol. 55, pp. 7387-7391, 2016.
[83] P. Zuo, B. Zhao, S. Yan, G. Yue, H. Yang, Y. Li, H. Wu, Y. Jiang, H. Jia, and J. Zhou, "Improved optical and electrical performances of GaN-based light emitting diodes with nano truncated cone SiO2 passivation layer," Optical and Quantum Electronics, vol. 48, pp. 288, 2016.
[84] Z. Liu, C. Zhu, Y. Wang, Y. Shen, H. Yang, C. Gu, J. Li, B. Liu, and X. Xu, "Light emitting enhancement and angle-resolved property of surface textured GaN-based vertical LED," Journal of Optics, vol. 45, pp. 81-86, 2016.
[85] Y.C. Yao, J.M. Hwang, Z.P. Yang, J.Y. Haung, C.C. Lin, W.C. Shen, C.Y. Chou, M.T. Wang, C.Y. Huang, and C.Y. Chen, "Enhanced external quantum efficiency in GaN-based vertical-type light-emitting diodes by localized surface plasmons," Scientific reports, vol. 6, pp. 22659, 2016.
[86] J.K. Liou, W.C. Chen, C.H. Chang, Y.C. Chang, J.H. Tsai, and W.C. Liu, "Enhanced light extraction of a high-power GaN-based light-emitting diode with a nanohemispherical hybrid backside reflector," IEEE Transactions on Electron Devices, vol. 62, pp. 3296-3301, 2015.
[87] Y.C. Shih, G. Kim, J.-P. You, and F.G. Shi, "Optical interaction between LED backside reflectors and die attach adhesives," IEEE Photonics Technology Letters, vol. 28, pp. 1446-1449, 2016.
[88] C.Y. Chen, and W.C. Liu, "Light extraction enhancement of gan-based light-emitting diodes with textured sidewalls and ICP-transferred nanohemispherical backside reflector," IEEE Transactions on Electron Devices, vol. 64, pp. 3672-3677, 2017.
[89] C.Y. Chen, W.C. Chen, C.H. Chang, Y.L. Lee, and W.C. Liu, "Implementation of light extraction improvements of GaN-based light-emitting diodes with specific textured sidewalls," Optics & Laser Technology, vol. 101, pp. 172-176, 2018.
[90] Y.L. Lee, and W.C. Liu, "Enhanced light extraction of GaN-based light-emitting diodes with a hybrid structure incorporating microhole arrays and textured sidewalls," IEEE Transactions on Electron Devices, vol. 65, pp. 3305-3310, 2018.
[91] C.H. Chang, Y.L. Lee, Z.F. Wang, R.C. Liu, J.H. Tsai, and W.C. Liu, "Performance Improvement of GaN-Based Light-Emitting Diodes With a Microhole Array, 45° Sidewalls, and a SiO2 Nanoparticle/Microsphere Passivation Layer," IEEE Transactions on Electron Devices, vol. 66, pp. 505-511, 2018.
[92] F.I. Lai, S. Ling, C. Hsieh, T. Hsueh, H.C. Kuo, and T.C. Lu, "Extraction efficiency enhancement of GaN-based light-emitting diodes by microhole array and roughened surface oxide," IEEE Electron Device Letters, vol. 30, pp. 496-498, 2009.
[93] J.K. Huang, C.Y. Liu, T.P. Chen, H.W. Huang, F.I. Lai, P.T. Lee, C.H. Lin, C.Y. Chang, T.S. Kao, and H.C. Kuo, "Enhanced light extraction efficiency of GaN-based hybrid nanorods light-emitting diodes," IEEE Journal of Selected Topics in Quantum Electronics, vol. 21, pp. 354-360, 2015.
[94] J.K. Liou, Y.C. Chan, W.C. Chen, C.H. Chang, C.Y. Chen, J.-H. Tsai, and W.C. Liu, "Characteristics of GaN-based LEDs with hybrid microhole arrays and SiO2 microspheres/nanoparticles structures," IEEE Transactions on Electron Devices, vol. 64, pp. 2854-2858, 2017.
[95] P. Kumnorkaew, Y.-K. Ee, N. Tansu, and J.F. Gilchrist, "Investigation of the deposition of microsphere monolayers for fabrication of microlens arrays," Langmuir, vol. 24, pp. 12150-12157, 2008.
[96] P. Kumnorkaew, A.L. Weldon, and J.F. Gilchrist, "Matching constituent fluxes for convective deposition of binary suspensions," Langmuir, vol. 26, pp. 2401-2405, 2009.
[97] P. Wayner Jr, "Interfacial profile in the contact line region of a finite contact angle system," Journal of Colloid and Interface Science, vol. 77, pp. 495-500, 1980.
[98] K. Stephan, L.C. Zhong, and P. Stephan, "Influence of capillary pressure on the evaporation of thin liquid films," Heat and mass transfer, vol. 30, pp. 467-472, 1995.
[99] R.D. Deegan, O. Bakajin, T.F. Dupont, G. Huber, S.R. Nagel, and T.A. Witten, "Capillary flow as the cause of ring stains from dried liquid drops," Nature, vol. 389, pp. 827, 1997.
[100] P.I. Stavroulakis, N. Christou, and D. Bagnall, "Improved deposition of large scale ordered nanosphere monolayers via liquid surface self-assembly," Materials Science and Engineering: B, vol. 165, pp. 186-189, 2009.
[101] S.J. So, and C.B. Park, "Improvement of brightness with Al2O3 passivation layers on the surface of InGaN/GaN-based light-emitting diode chips," Thin Solid Films, vol. 516, pp. 2031-2034, 2008.
[102] H.-Y. Liu, W.-C. Hsu, B.-Y. Chou, Y.-H. Wang, W.-C. Sun, S.-Y. Wei, and S.-M. Yu, "Al2O3 passivation layer for InGaN/GaN LED deposited by ultrasonic spray pyrolysis," IEEE Photonics Technology Letters, vol. 26, pp. 1243-1246, 2014.
[103] S.H. Kim, H.H. Park, Y.H. Song, H.J. Park, J.B. Kim, S.R. Jeon, H. Jeong, M.S. Jeong, and G.M. Yang, "An improvement of light extraction efficiency for GaN-based light emitting diodes by selective etched nanorods in periodic microholes," Optics express, vol. 21, pp. 7125-7130, 2013.
[104] Y. Muramoto, M. Kimura, and S. Nouda, "Development and future of ultraviolet light-emitting diodes: UV-LED will replace the UV lamp," Semiconductor Science and Technology, vol. 29, pp. 084004, 2014.
[105] Y. Chen, D. Yuan, M. Yang, D. Wang, and X. Sun, "High efficiency GaN LEDs with submicron-scale 2Dperiodic structures directly fabricated by laser interference ablation," Optics & Laser Technology, vol. 90, pp. 211-215, 2017.
[106] K. Lee, C.-R. Lee, T.-H. Chung, J. Park, J.-Y. Leem, K.-U. Jeong, and J.S. Kim, "Influences of graded superlattice on the electrostatic discharge characteristics of green InGaN/GaN light-emitting diodes," Journal of Crystal Growth, vol. 464, pp. 138-142, 2017.
[107] J. Zhu, H. Zhang, Z. Zhu, Q. Li, and G. Jin, "Surface-plasmon-enhanced GaN-LED based on the multilayered rectangular nano-grating," Optics Communications, vol. 322, pp. 66-72, 2014.
[108] K. Xu, Y. Xie, H. Ma, Y. Du, F. Zeng, P. Ding, Z. Gao, C. Xu, and J. Sun, "ZnO nanorods/graphene/Ni/Au hybrid structures as transparent conductive layer in GaN LED for low work voltage and high light extraction," Solid-State Electronics, vol. 126, pp. 5-9, 2016.
[109] H. Wang, H. Li, Y. Lee, H. Sato, K. Yamashita, T. Sugahara, and S. Sakai, "Fabrication of high-performance 370 nm ultraviolet light-emitting diodes," Journal of crystal growth, vol. 264, pp. 48-52, 2004.
[110] C.Y. Cho, K.H. Park, and S.J. Park, "Enhanced Optical Output Power of Blue Light-Emitting Diode Grown on Sapphire Substrate with Patterned Distributed Bragg Reflector," ECS Journal of Solid State Science and Technology, vol. 7, pp. Q66-Q69, 2018.
[111] J.-C. Su, C.-H. Lee, Y.-H. Huang, and H. Yang, "In-situ mapping of electroluminescent enhancement of light-emitting diodes grown on patterned sapphire substrates," Journal of Applied Physics, vol. 121, pp. 055705, 2017.
[112] B. Yonkee, E. Young, S. DenBaars, S. Nakamura, and J. Speck, "Silver free III-nitride flip chip light-emitting-diode with wall plug efficiency over 70% utilizing a GaN tunnel junction," Applied Physics Letters, vol. 109, pp. 191104, 2016.
[113] S.E. Brinkley, C.L. Keraly, J. Sonoda, C. Weisbuch, J.S. Speck, S. Nakamura, and S.P. DenBaars, "Chip shaping for light extraction enhancement of bulk c-plane light-emitting diodes," Applied Physics Express, vol. 5, pp. 032104, 2012.
[114] J.Y. Kim, M.K. Kwon, J.P. Kim, and S.J. Park, "Enhanced light extraction from triangular GaN-based light-emitting diodes," IEEE Photonics Technology Letters, vol. 19, pp. 1865-1867, 2007.
[115] J.K. Kim, T. Gessmann, H. Luo, and E.F. Schubert, "GaInN light-emitting diodes with RuO2/SiO2/Ag omni-directional reflector," Applied Physics Letters, vol. 84, pp. 4508-4510, 2004.
[116] R.M. Lin, Y.C. Lu, Y.L. Chou, G.H. Chen, Y.H. Lin, and M.C. Wu, "Enhanced characteristics of blue InGaN/GaN light-emitting diodes by using selective activation to modulate the lateral current spreading length," Applied Physics Letters, vol. 92, pp. 261105, 2008.
[117] Y.C. Chang, J.K. Liou, and W.C. Liu, "Improved light extraction efficiency of a high-power GaN-based light-emitting diode with a three-dimensional-photonic crystal (3-D-PhC) backside reflector," IEEE Electron Device Letters, vol. 34, pp. 777-779, 2013.
[118] Y.J. Liu, C.C. Huang, T.Y. Chen, C.S. Hsu, J.K. Liou, and W.C. Liu, "Improved performance of an InGaN-based light-emitting diode with a p-GaN/n-GaN barrier junction," IEEE Journal of Quantum Electronics, vol. 47, pp. 755-761, 2011.
[119] Y. Chen, Z. Chen, S. Jiang, C. Li, Y. Chen, J. Zhan, X. Kang, F. Jiao, G. Zhang, and B. Shen, "Fabrication of nano-patterned sapphire substrates by combining nanoimprint lithography with edge effects," CrystEngComm, vol. 21, pp. 1794-1800, 2019.
[120] T. Gessmann, E. Schubert, J. Graff, K. Streubel, and C. Karnutsch, "Omnidirectional reflective contacts for light-emitting diodes," IEEE Electron Device Letters, vol. 24, pp. 683-685, 2003.
[121] S.J. Chang, C. Shen, M. Hsieh, C. Kuo, T. Ko, W. Chen, and S.-C. Shei, "Nitride-Based LEDs With a Hybrid Al Mirror TiO2/SiO2 DBR Backside Reflector," Journal of lightwave technology, vol. 26, pp. 3131-3136, 2008.
[122] Q. Zhang, K. Li, and H. Choi, "InGaN light‐emitting diodes with indium‐tin‐oxide sub‐micron lenses patterned by nanosphere lithography," Applied Physics Letters, vol. 100, pp. 061120, 2012.
[123] K.M. Huang, H.J. Chang, C.L. Ho, and M.C. Wu, "Enhanced light extraction efficiency of GaN-based LEDs with 3-D colloidal-photonic-crystal bottom reflector," IEEE Photonics Technology Letters, vol. 24, pp. 1298-1300, 2012.
[124] E. Samwel, P. Bissell, and J. Lodder, "Remanent magnetic measurements on perpendicular recording materials with compensation for demagnetizing fields," Journal of applied physics, vol. 73, pp. 1353-1359, 1993.
[125] L. Shan, T. Wei, Y. Sun, Y. Zhang, Z. Xiong, A. Zhen, J. Wang, Y. Wei, and J. Li, "Effect of layers of carbon-nanotube-patterned substrate on GaN-based light-emitting diodes," Japanese Journal of Applied Physics, vol. 54, pp. 065102, 2015.
[126] X. Zou, X. Zhang, W.C. Chong, C.W. Tang, and K.M. Lau, "Vertical LEDs on rigid and flexible substrates using GaN-on-Si epilayers and Au-free bonding," IEEE Transactions on Electron Devices, vol. 63, pp. 1587-1593, 2016.
[127] E. Kuramochi, "Manipulating and trapping light with photonic crystals from fundamental studies to practical applications," Journal of Materials Chemistry C, vol. 4, pp. 11032-11049, 2016.
[128] J.K. Kim, A.N. Noemaun, F.W. Mont, D. Meyaard, E.F. Schubert, D.J. Poxson, H. Kim, C. Sone, and Y. Park, "Elimination of total internal reflection in GaInN light-emitting diodes by graded-refractive-index micropillars," Applied Physics Letters, vol. 93, pp. 221111, 2008.
[129] S.M. Pan, R.C. Tu, Y.M. Fan, R.C. Yeh, and J.T. Hsu, "Improvement of InGaN-GaN light-emitting diodes with surface-textured indium-tin-oxide transparent ohmic contacts," IEEE Photonics Technology Letters, vol. 15, pp. 649-651, 2003.
[130] J.K. Kim, S. Chhajed, M.F. Schubert, E.F. Schubert, A.J. Fischer, M.H. Crawford, J. Cho, H. Kim, and C. Sone, "Light‐extraction enhancement of GaInN light‐emitting diodes by graded‐refractive‐index indium tin oxide anti‐reflection contact," Advanced materials, vol. 20, pp. 801-804, 2008.
[131] S.P. ReddyáM, "High-performance light-emitting diodes using hierarchical m-plane GaN nano-prism light extractors," Journal of Materials Chemistry C, vol. 3, pp. 8873-8880, 2015.
[132] C.H. Chan, A. Fischer, A. Martinez-Gil, P. Taillepierre, C.C. Lee, S.L. Yang, C.-H. Hou, H.T. Chien, D.P. Cai, and K.C. Hsu, "Anti-reflection layer formed by monolayer of microspheres," Applied Physics B, vol. 100, pp. 547-551, 2010.
[133] S.Y. Kuo, K.B. Hong, and T.C. Lu, "Enhanced light output of UVA GaN vertical LEDs with novel DBR mirrors," IEEE Journal of Quantum Electronics, vol. 51, pp. 1-5, 2015.
[134] F. Járai-Szabó, Z. Néda, S. Aştilean, C. Farcău, and A. Kuttesch, "Shake-induced order in nanosphere systems," The European Physical Journal E, vol. 23, pp. 153-159, 2007.
[135] Y.J. Liu, C.C. Huang, T.Y. Chen, C.S. Hsu, S.Y. Cheng, K.W. Lin, J.K. Liou, and W.C. Liu, "Improved performance of GaN-based light-emitting diodes by using short-period superlattice structures," Progress in Natural Science: Materials International, vol. 20, pp. 70-75, 2010.
[136] Y.C. Tu, S.J. Wang, G.Y. Lin, T.H. Lin, C.H. Hung, F.S. Tsai, K.M. Uang, and T.M. Chen, "Enhanced light output of vertical GaN-based LEDs with surface roughened by refractive-index-matched Si3N4/GaN nanowire arrays," Applied Physics Express, vol. 7, pp. 042101, 2014.