本論文主要為應用奈米結構與圖案化藍寶石基板來改善氮化鎵系列之發光二極體，其中奈米結構之研究包含，¬二維與三維奈米球陣列、奈米銀粒子陣列與布拉格反射鏡電流散佈層，而圖案化藍寶石基板之研究包含，利用奈米球微影術、奈米壓印微影術與二氧化矽微米柱陣列製作不同之圖案化藍寶石基板。最後使用晶圓鍵合與化學機械式研磨技術，轉移氮化鎵磊晶層到導電性較佳之基板上並將藍寶石基板移除。
於應用奈米結構改善氮化鎵發光二極體之研究中，第一部份我們成功地利用旋轉塗佈法將聚苯乙烯與二氧化矽奈米球均勻塗佈於發光二極體之表面與側面，適當的控制旋轉塗佈參數形成均勻之單層與多層奈米球陣列，單層聚苯乙烯與多層二氧化矽奈米球陣列塗佈於晶片表面與側面時可分別提升發光強度達9與19%。第二部分利用奈米球微影術製作出奈米銀陣列，藉由控制奈米球的大小與銀蒸鍍的厚度可以精準控制表面電漿子之共振頻率，在適當條件下，藉由表面電漿子與多重量子井之耦合效應，光輸出功率可提升約15.4%。最後在p型電極下方製作高反射率布拉格反射鏡電流散佈層，絕緣之布拉格反射鏡可有效增加電流散佈並避免電極吸光之效應，使光輸出功率提升16.8%，與具二氧化矽電流散佈層之發光二極體比較約可提升11.3%。
於應用圖案化藍寶石基板改善發光二極體之研究中，第一部份我們成功地利用奈米球微影術製作出奈米圖案化藍寶石基板，相較於使用微米圖案化藍寶石基板來成長氮化鎵發光二極體，使用奈米圖案化藍寶石基板之發光二極體可提升約11%的光輸出功率，第二部分將氮化鎵發光二極體結構直接異質磊晶成長於二氧化矽微米柱陣列之上，藉由橫向磊晶成長機制可改善晶格品質，接著利用氧化物緩衝蝕刻液移除二氧化矽微米柱陣列後，在晶粒週圍形成空氣微米孔洞陣列，再利用氫氧化鈉溶液將空氣微米孔洞陣列蝕刻成倒金字塔的形狀後，光輸出功率可提升18.4%。第三部分利用奈米壓印微影術製作出具不同圖案大小與不同深寬比之圖案化藍寶石基板，實驗結果顯示較小之圖案有較佳的光取出效率,而適當選擇圖案之大小與深度可獲得最佳晶格品質。另外奈米圖案化藍寶石基板之深寬比也強烈影響發光二極體元件之光取出效率。
最後，藉由晶圓鍵合技術將成長於藍寶石基板之氮化鎵磊晶層與鉬基板結合，藉由熱膨脹係數接近之鉬基板可有效減少晶片鍵合後之翹曲現象。另外並利用化學機械研磨技術將藍寶石基板緩慢移除，將藍寶石基板厚度從450微米研磨到介於1.1與20.3微米，藉由微拉曼與光激發光譜儀進行應力量測，發現當厚度為1.1微米時應力約釋放248.3兆帕，而接近線性之能帶間隙與藍寶石基板厚度之關係也被發現，此關係斜率約為 -6.52 毫電子伏特/微米。

The main purpose of this dissertation is to develop high efficiencies of GaN-based light-emitting diodes (LEDs) by applying nanostructures and patterned sapphire substrates (PSSs). The investigation of nanostructures including two dimensional (2D) and three dimensional (3D) nanosphere layers, silver nanotriangle array (NTA),　and distributed Bragg reflector (DBR) current blocking layer (CBL). The investigation of PSS, we utilized the nanosphere lithography, nanoimprint lithography, and SiO2 micro-rods array to fabricate different PSSs. Finally, wafer bonding and chemical mechanical polishing (CMP) processes are introduced as a means to transfer GaN thin-film onto a conductive substrate and then remove the sapphire substrate.
In respect of research on nanostructures, the polystyrene (PS) and SiO2 nanospheres were spun uniformly onto the top and sidewall surface of GaN LEDs. With proper control the coating parameters, the PS and SiO2 nanospheres can be self-aligned to form a closely packed single and mutiple nanosphere layers. Compared with the LED without nanosphere layers, the luminance intensities of the LEDs with PS nanosphere single layer on the top surface and SiO2 multiple nanosphere layers on the sidewall surface of LEDs were seen to increase by 9 and 19% at 20 mA, respectively. The Ag NTA was fabricated by nanosphere lithography. The resonant frequency of a generated localized surface plasmon (LSP) can be precisely controlled by changing the size of the PS nanosphere and the Ag deposition thickness. Under the optimum conditions, the light output power of LED with an Ag NTA was 15.4 % higher than LED without an Ag NTA at an inject current of 20 mA. The improvement in light output power can be attributed to the coupling effect between MQW and LSP. Furthermore, we have demonstrated GaN LEDs with DBR CBL beneath the p-pad electrodes. At a driving current of 20 mA, the light output power of the LEDs with DBR CBL was increased by 16.8 and 11.3% as compared with the LEDs without and with a SiO2 CBL. The improvement is contributed to the DBR CBL can deflect the current away from the p-electrode pads, but also prevent the light absorption by the opaque metal electrodes.
In respect of research on PSS, first, nano-scale PSS (NPSS) was successfully demonstrated by using nanosphere lithography. By introducing NPSS, the output power of LED grown on micro-scale PSS could increase by 11%. Second, the GaN LEDs direct heteroepitaxial lateral overgrowth with SiO2 micro-rods array has been demonstrated.　Lateral overgrowth of GaN layers with the SiO2 micro-rods array can be improved epitaxial GaN film quality. Then, buffer oxide etching (BOE) solution was used to remove SiO2 micro-rods array to formation of the periodic micro-hole array surrounding the LED and NaOH solution was used to etch the sidewalls again into inverted pyramid shape. The light output power could be further enhanced about 18.36 % as compared with the conventional LEDs when adopting the textured sidewall surface. Third, the NPSSs with various aspect ratios and pattern sizes were fabricated by nanoimprint lithography. Experimental results indicated that the smaller pattern size facilitates superior light extraction efficiency and a suitable pattern size and etching depth with the lowest FWHM in rocking curve should be chosen to get the high quality of GaN film. However, the aspect ratio of the NPSS is also strongly related to the performance of LEDs.
Finally, GaN epilayers was transferred onto a Mo substrate through a wafer bonding process. A CTE-matched Mo substrate can be used for the reduction of wafer warpage during the wafer bonding process. Moreover, sapphire substrates were removed slowly by CMP technique. By reducing the thickness of the sapphire substrate from 450 μm to the range between 1.1 μm and 20.3 μm, the stress effects in GaN epilayers on very thin sapphire substrates are analyzed by Raman spectroscopy and photoluminescence. By analyzing the main scattering signal of E2 (high) mode, the thinnest sample (1.1 μm) exhibits a 248.3 MPa (1.54 cm-1) stress relaxation. An almost linear relationship between residual sapphire thickness and energy bandgap was also observed during the CMP process, the slope was -6.52 meV/μm.

[1] H. J. Round, “A note on carborundum,” Electrical World, vol. 19, pp. 309–312, 1907.
[2] H. Welker, “On new semiconducting compounds,” Zeitschrift fur Naturforschung, vol. 7a, pp. 744–749, 1952.
[3] H. Welker, “On new semiconducting compounds II,” Zeitschrift fur Naturforschung, vol. 8a, pp. 248–251, 1953.
[4] R. Braunstein,“ Radiative Transitions in Semiconductors,” Phys. Rev, vol. 99, pp. 1892–1893, 1955.
[5] J. N. Holonyak and S. F. Bevacqua, “Coherent (visible) light emission from Ga(As1-xPx) junctions,” Appl. Phys. Lett., vol. 1, pp. 82–83, 1962.
[6] H. P. Maruska, and J. J. Tietjen, “The preparation and properties of vapour-deposited single-crystal-line GaN,” Appl. Phys. Lett., vol. 15, p. 327, 1969.
[7] J. I. Pankove, E. A. Miller, D. Richman, and J. E. Berkeyheiser, “Electroluminescence in GaN,” J. Luminescence, vol. 4, pp. 63–66, 1971.
[8] 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,”Appl. Phys. Lett. vol. 48, pp. 353–355, 1986.
[9] 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.
[10] S. Nakamura and T. Mukai, “High-quality InGaN films grown on GaN films,” Jpn. J. Appl. Phys., vol. 31, pp. L457–L459, 1992.
[11] P. Kung, C. J. Sun, A. Saxler, H. Ohsato, and M. Razeghi, “Crystallography of epitaxial growth of wurtzite-type thin films on sapphire substrates,” J. Appl. Phys., vol. 75, pp. 4515–4519, 1994.
[12] S. Nakamura, N. Iwasa, and M. Senoh, “Method of manufacturing p-type compound semiconductor,” U.S. Patent 5,306,662, April 26, 1994.
[13] S. Nakamura, M. Senoh, N. Iwasa, S. Nagahama, T. Yamada, T. Mukai, “Superbright Green InGaN Single-Quantum-Well-Structure Light-Enmitting Diodes,” Jpn. J. Appl. Phys. vol.34, pp.L1332-L1335, 1995.
[14] K. H. Huang and T. P. Chen, “Light-emitting diode structure,” U.S. Patent 5,661,742, August 26, 1997.
[15] T. Sasaki and T. Matsuoka, “Substrate-polarity dependence of metal-organic vapor-phase-epitaxy-grown GaN on SiC,” J. Appl. Phys., vol. 64, pp.4531–4535, 1988.
[16] C. J. Sun, P. Kung, A. Saxler, H. Ohsato, E. Bigan, and M. Razeghi, “Thermal stability of GaN thin films grown on (0001) Al2O3, (01-12) Al2O3, and (0001)Si SiC substrates,” J. Appl. Phys., vol. 76, pp. 236–241, 1994.
[17] Y. Sun, Y. H. Cho, H. M. Kim and T. W. Kang, “High efficiency and brightness of blue light emission from dislocation-free InGaN/GaN quantum well nanorod arrays,”Appl. Phys. Lett. vol. 87, pp. 093115, 2005.
[18] C. Huh, J. M. Lee, D. J. Kim, and S. J. Park, “Improvement in light-output efficiency of InGaN/GaN multiple-quantum well light-emitting diodes by current blocking layer,” J. Appl. Phys., vol. 92, pp. 2248–2250, 2002.
[19] A. Sakai, H. Sunakawa, and A. Usui, “Defect structure in selectively grown GaN films with low threading dislocation density,” Appl. Phys. Lett., vol. 71, pp. 2259–2261, 1997.
[20] 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” Jpn. J. Appl. Phys. vol. 41, pp. L 1431–L1433, 2002.
[21] T. P. Chen, T. C. Hsu, C. Y. Luo, M. C. Hsu, and T. X. Lee, “Improvement in Light Extraction Efficiency of High Brightness InGaN-Based Light Emitting Diodes,” Proc. SPIE, vol. 7216, pp. 1–10, 2009.
[22] P. B. Fischer and S. Y. Chou, “High resolution electron beam lithography and high accuracy overlay using a modified SEM”, Microelectronic Engineering, vol. 21, pp. 141-144, 1993.
[23] 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,” Jpn J. Appl. Phys., vol. 43, pp. 5809-5813, 2004.
[24] F. Romanato, L. Businaro, L. Vaccari, S. Cabrini, P. Candeloro, M. De Vittorio , A. Passaseo , M.T. Todaro , R. Cingolani , E. Cattaruzza ,M. Galli , C. Andreani , E. Di Fabrizio, “Fabrication of 3D metallic photonic crystals by X-ray lithography”, Microelectronic Engineering vol. 67–68, pp. 479–486, 2003.
[25] D. H. Kim, C. O. Cho, Y. G. Roh, H. Jeon, and Y. S. Park, “Enhanced light extraction from GaN-based light-emitting diodes with holographically generated two-dimensional photonic crystal patterns,” Appl. Phys. Lett., vol. 87, pp. 203508, 2005.
[26] H. W. Deckman and J. H. Dunsmuir, “Applications of surface textures produced with natural lithography,” J. Vac. Sci. Technol. B, Microelectron.Process. Phenom., vol. 1, pp. 1109–1112, 1983.
[27] M. Winzer, M. Kleiber, N. Dix, and R. Wiesendanger, “Fabrication of nano-dot- and nano-ring-arrays by nanosphere lithography,” Appl. Phys. A, vol. 63, pp. 617–619, 1996.
[28] S. Han, Z. Hao, J. Wang, and Y. Luo, “Controllable two-dimensional photonic crystal patterns fabricated by nanosphere lithography”, J. Vac. Sci. Technol. B vol. 23, pp. 1585-1588, 2005.
[29] J. H. Zhang, Y. F. Li, X. M. Zhang, and B. Yang, “Colloidal Self-Assembly Meets Nanofabrication: From Two-Dimensional Colloidal Crystals to Nanostructure Arrays”, Adv. Mater. vol.22, pp. 4249-4269, 2004.
[30] J. Y. Kim, M. K. Kwon, K. S. Lee, and S. J. Park, “Enhanced light extraction from GaN-based green light-emitting diode with photonic crystal,” Appl. Phys. Lett., vol. 91, pp. 181109, 2007.
[31] K. J. Byeon, S. Y. Hwang, and H. Lee, “Fabrication of two-dimensional photonic crystal patterns on GaN-based light-emitting diodes using thermally curable monomer-based nanoimprint lithography,” Appl. Phys. Lett., vol. 91, pp. 091106, 2007.
[32] N. D. Denkov, O. D. Velev, P. A. Kralchevsky, I. B. Ivanov, H. Yoshimura, and K. Nagayama, “Two-dimensional crystallization,” Nature, vol. 361, pp. 26, 1993.
[33] D. J. Norris, E. G. Arlinghaus, L. Meng, R. Heiny, and L. E. Scriven, “Opaline Photonic Crystal: How does self-assembly work”, Adv. Mater. vol.16, pp. 1393, 2004.
[34] F. Jarai-Szabo, S. Astilean and Z. Neda, “Understanding self-assembled nanosphere patterns”, Chemical Physics Letters, vol. 408, pp. 241–246, 2005.
[35] Yan Xu, Garrett J. Schneider, Eric D. Wetzel, and Dennis W. Prather, “Fabrication of self-assembled photonic-crystal structures by centrifugation and spin-coating”, proceedings of SPIE - The International Society for Optical Engineering, vol. 5183, pp. 16-24, 2003.
[36] S. Venkatesh, P. Jiang, and B. Jiang, “Generalized Fabrication of Two-Dimensional Non-Close-Packed Colloidal Crystals”, Langmuir, vol. 23, pp. 8231-8235, 2007.
[37] J. Rybczynski, U. Ebels, M. Giersig, “Large-scale, 2D arrays of magnetic nanoparticles”, Colloids and Surfaces A: Physicochemical and Engineering Aspects, vol. 219, pp. 1-6, 2003.
[38] N. H. Finkel, B. G. Prevo, O. D. Velev, and L. He, “Ordered Silicon Nanocavity Arrays in Surface-Assisted Desorption/Ionization Mass Spectrometry”, Analytical Chemistry, vol. 77, pp. 1088-1095, 2005.
[39] E. F. Schubert, “Light Emitting Diodes”, Cambridge, U.K.: Cambridge Univ. Press, 2003.
[40] T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett., vol. 84, pp. 855-857, 2004.
[41] C. M. Tsai, J. K. Sheu, W. C. Lai, Y. P. Hsu, P. T. Wang, C. T. Kuo, C. K. Kuo, S. J. Chang, and Y. K. Su, “Enhanced output power in GN-based LEDs with naturally textured surface grown by MOCVD,” IEEE Electron Dev. Lett., vol. 26, pp. 464-466, 2005.
[42] W. C. Peng and Y. S. Wu, ‘Enhanced Light Output in Double Roughened GaN Light-Emitting Diodes via Various Texturing Treatments of Undoped-GaN Layer,” Jpn. J. Appl. Phys., Part 1, vol. 45, pp. 7709-7712, 2006.
[43] J. Shakya, K. H. Kim, J. Y. Lin, and H. X. Jiang, “Enhanced light extraction in III-nitride ultraviolet photonic crystal light-emitting diodes,” Appl. Phys. Lett., vol. 85, pp. 142-144, 2004.
[44] J. J. Wierer, M. R. Krames, J. E. Epler, N. F. Gardner, M. G. Craford, J. R. Wendt, J. A. Simmons, and M. M. Sigalas, “InGaN/GaN quantum-well heterostructure light-emitting diodes employing photonic crystal structures,” Appl. Phys. Lett., vol. 84, pp. 3885-3887, 2004.
[45] C. C. Kao, H. C. Kuo, H. W. Huang, J. T. Chu, Y. C. Peng, Y. L. Hsieh, C. Y. 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 Photon. Technol. Lett., vol. 17, pp. 19-21, 2005.
[46] C. C. Kao, Y. K. Su, Fellow, IEEE, C. L. Lin, and J. J. Chen, “Efficiency Improvement of GaN-Based LEDs With SiO2 Micro-Rods Array and Textured Sidewalls,” IEEE Electron Dev. Lett., vol. 31, pp. 35-37, 2010.
[47] K. Tadatomo, H. Okagawa, Y. Ohuchi, T. Tsunekawa, Y. Imada, M. Kato, and T. Taguchi, “High output power InGaN ultraviolet light emitting diodes fabricated on patterned substrates using metalorganic vapor phase epitaxy,” Jpn. J. Appl. Phys., vol. 40, pp. L583–L585, 2001.
[48] Z. H. Feng and K. M. Lau, “Enhanced luminescence from GaN-based blue LEDs grown on grooved sapphire substrates,” IEEE Photon. Technol. Lett., vol. 17, pp. 1812–1814, 2005.
[49] W. K. Wang, D. S. Wuu, S. H. Lin, P. Han, R. H. Horng, T. C. Hsu, D. T. C. Huo, M. J. Jou, Y. H. Yu, and A. Lin, “Efficiency improvement of near-ultraviolet InGaN LEDs using patterned sapphire substrates,” IEEE J. Quantum Electron., vol. 41, pp. 1403–1409, 2005.
[50] 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, pp. 1152–1154, 2006.
[51] C. C. Wang, H. Ku, C. C. Liu, K. K. Chong, C. I Hung, Y. H. Wang, and M. P. Houng, “Enhancement of the light output performance for GaN-based light-emitting diodes by bottom pillar structure,” Appl. Phys. Lett., vol. 91, pp. 121109-1–3, 2007.
[52] H. Gao, F. Yan, Y. Zhang, J. Li, Y. Zeng, and G. Wang, “Enhancement of the light output power of InGaN/GaN light-emitting diodes grown on pyramidal patterned sapphire substrates in the micro- and nanoscale,” J. Appl. Phys., vol. 103, pp. 014314-1–5, 2008.
[53] C. H. Chiu, H. H. Yen, C. L. Chao, Z. Y. Li, Peichen Yu, H. C. Kuo, T. C. Lu, S. C. Wang, K. M. Lau, and S. J. Cheng, “Nanoscale epitaxial lateral overgrowth of GaN-based light-emitting diodes on a SiO2 nanorod-array patterned sapphire template,” Appl. Phys. Lett., vol. 93, pp. 081108-1–3, 2008.
[54] Y. K. Ee, X. H. Li, J. Biser, W. J. Cao, H. M.Chan, R. P. Vinci, and N. Tansu, “Abbreviated MOVPE nucleation of III-nitride light-emitting diodes on nano-patterned sapphire,” J. Crystal Growth, vol. 312, pp. 1311–1315, 2010.
[55] H. W. Huanga, C. H. Lin, J. K. Huang, K. Y. Lee, C. F. Lin, C. C. Yu, J. Y. Tsai, R. Hsueh, H. C. Kuo, and S. C.Wang, “Investigation of GaN-based light emitting diodes with nano-hole patterned sapphire substrate (NHPSS) by nano-imprint lithography,” Mater. Sci. Eng. B, vol. 164, pp. 76–79, 2009.
[56] H. Heinke, V. Kirchner, S. Einfeldt, and D. Hommel, “X-ray diffraction analysis of the defect structure in epitaxial GaN,” Appl. Phys. Lett., vol. 77, pp. 2145–2147, 2000.
[57] A. Neogi, C. W. Lee, H. O. Everitt, T. Kuroda, A Tackeuchi, and E. Yablonvitch, “Enhancement of spontaneous recombination rate in a quantum well by resonant surface plasmon coupling,” Phys. Rev. B., vol. 66, pp 153305-1-4, 2002.
[58] J. J. Mock, M. Barbic, D. R. Smith, D. A. Schultz, and S. Schultz, “Shape effects in plasmon resonance of individual colloidal silver nanoparticles,” J. Chem. Phys., vol. 116, pp 6755-6759, 2002.
[59] K. H. Su, Q. H. Wei, X. Zhang, J. J. Mock, D. R. Smith, and S. Schultz, “Interparticle Coupling Effects on Plasmon Resonances of Nanogold Particles,” Nano Lett., vol. 3, pp 1087-1090, 2003.
[60] K. Okamoto, I. Niki, A. Scherer, Y. Narukawa, T. Mukai, and Y. Kawakami, “Surface plasmon enhanced spontaneous emission rate of InGaN/GaN,” Appl. Phys. Lett., vol. 87, pp. 071102-1-3, 2005.
[61] K. A. Willets and R. P. V. Duyne, “Localized surface plasmon resonance spectroscopy and sensing,” Annu. Rev. Phys. Chem., vol. 58, pp 267-297, 2007.
[62] W. L. Barnes, A. Dereux and T. W. Ebbesen, “Surface Plasmon subwavelength optics,” Nature., vol. 424, pp 824-830, 2003.
[63] P. A. Hobson, S. Wedge, J. A. E. Wasey, I. Sage, and W. L. Barnes, “Surface plasmon mediated emission from organic light-emitting diodes,” Adv. Mater., vol. 14, pp. 1393-1396, 2002.
[64] K. Okamoto, I. Niki, A. Shvartser, Y. Narukawa, T. Mukai, A. Scherer, “Surface-plasmon-enhanced light emitters based on InGaN quantum wells ,” Nat. Mater., vol. 3, pp 601-605, 2004.
[65] D. M. Yeh, C. F. Huang, C. Y. Chen, Y. C. Lu, and C. C. Yang, “Surface plasmon coupling effect in an InGaN/GaN single-quantum-well light-emitting diode,” Appl. Phys. Lett., vol. 91, pp. 171103-1-3, 2007.
[66] M. K. Kwon, J. Y. Kim, B. H. Kim, I. K. Park, C. Y. Cho, C. C. Byeon, and S. J. Park, “Surface-Plasmon-Enhanced Light-Emitting Diodes,” Adv. Mater., vol. 20, pp. 1253-1257, 2008.
[67] D. M. Yeh, C. F. Huang, C. Y. Chen, Y. C. Lu and C. C. Yang, “Localized surface plasmon-induced emission enhancement of a green light-emitting diode,” Nanotechnology, vol. 19, pp. 345201–1-4, 2008.
[68] Y. K. Su, J. J. Chen, C. L. Lin, S. M. Chen, W. L. Li, and C. C. Kao, “GaN-Based Light-Emitting Diodes Grown on Photonic Crystal-Patterned Sapphire Substrates by Nanosphere Lithography, ” Jpn. J. Appl. Phys., vol. 47, pp. 6706–6708, 2008.
[69] I. Gontijo, M. Boroditsky, E. Yablonovitch, S. Keller, U. K. Mishra, and S. P. DenBaars, “Coupling of InGaN quantum-well photoluminescence to silver surface plasmons,” Phys. Rev. B., vol. 60, pp 11564-11567, 1999.
[70] J. K. Sheu, G. C. Chi, and M. J. Jou, “Enhanced output power in an InGaN–GaN multiquantum-well light-emitting diode with an InGaN current-spreading layer,” IEEE Photon. Technol. Lett., vol. 13, pp. 1164–1166, 2001.
[71] X. A. Cao, E. B. Stokes, P. Sandvik, N. Taskar, J. Kretchmer, and D. Walker, “Optimization of current spreading metal layer for GaN/InGaN-based light emitting diodes,” Solid-State Electronics., vol. 46, pp. 1235–1239, 2002.
[72] C. J. Tun, J. K. Sheu, B. J. Pong, M. L. Lee, M. Y. Lee, C. K. Hsieh, C. C. Hu, and G. C. Chi, “Enhanced light output of GaN-based power LEDs with transparent Al-doped ZnO current spreading layer,” IEEE Photon. Technol. Lett., vol. 18, pp. 274–276, 2006.
[73] Y. B. Lee, R. Takaki, H. Sato, Y. Naoi1, and S. Sakai, “High efficiency GaN-based LEDs using plasma selective treatment of p-GaN surface,” phys. stat. sol. (a)., vol. 200, pp. 87–90, 2003.
[74] H. C. Wang, Y. K. Su, C. L. Lin, W. B. Chen, and S. M. Chen, “InGaN/GaN light emitting diodes with a lateral current blocking structure,” Jpn. J. Appl. Phys., vol. 43, pp. 2006–2007, 2004.
[75] S. J. Chang, C. F. Shen, W. S. Chen, T. K. Ko, C. T. Kuo, K. H. Yu, S. C. Shei, and Y. Z. Chiou, “Nitride-Based LEDs with an Insulating SiO2 Layer Underneath p-Pad Electrodes,” Electrochem. Solid-State Lett., vol. 10, pp. H175-H177, 2007.
[76] M. A. Tsai, P. Yu, J. R. Chen, J. K. Huang, C. H. Chiu, H. C. Kuo, T. C. Lu, S. H. Lin, and S. C. Wang, “Improving Light Output Power of the GaN-Based Vertical-Injection Light-Emitting Diodes by Mg+ Implanted Current Blocking Layer,” IEEE Photon. Technol. Lett., vol. 21, pp. 688–690, 2009.
[77] 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, pp. 102103-1-102103-4, 2009.
[78] J. K. Sheu, I-Hsiu Hung, W. C. Lai, S. C. Shei, and M. L. Lee, “Enhancement in output power of blue gallium nitride-based light-emitting diodes with omnidirectional metal reflector under electrode pads,” Appl. Phys. Lett., vol. 93, pp. 103507-1-103507-3, 2008.
[79] S. C. Shei, W. C. Lai, J. K. Sheu, I. H. Hung, and S. J. Chang, “Effects of p-Electrode Reflectivity on Extraction Efficiency of Nitride-Based Light-Emitting Diodes” Appl. Phys. Express., Vol. 1, pp. 052001-1-052001-1, 2008.
[80] I. Akasaki, H. Amano, Y. Koide, K. Hiramatsu, and N. Sawaki, “Effects of an AlN buffer layer on crystallographic structure and on electrical and optical properties of GaN and Ga1−xAlxN (0<x<0.4) films grown on sapphire substrate by MOVPE,” J. Crystal Growth., vol. 98, pp. 209–219, 1989.
[81] S. Nakamura, “GaN growth using GaN buffer layer,” Jpn. J. Appl. Phys., vol. 30, pp. L1705–L1707, 1991.
[82] K. Hiramatsu, S. Itoh, H. Amano, I. Akasaki, N. Kuwano, T. Shiraishi, and K. Oki, “Growth mechanism of GaN grown on sapphire with AlN buffer layer by MOVPE,” J. Crystal Growth., vol. 115, pp. 628–633, 1991.
[83] F. A. Ponce, “Defects and interfaces in GaN epitaxy,” Mater. Res. Soc. Bull., vol. 22, pp. 51–57, 1997.
[84] H. Marchand, J. P. Ibbetson, P. T. Fini, P. Kozodoy, S. Keller, J. S. Speck, S. P. DenBaars, and U. K. Mishra, “Atomic force microscopy observation of threading dislocation density reduction in lateral epitaxial overgrowth of gallium nitride by MOCVD,” MRS Internet J. Nitride Semicond. Res., vol. 3, pp. 1-7, 1998.
[85] K. Hiramatsu, K. Nishiyama, M. Onishi, H. Mizutani, M. Narukawa, A. Motogaito, H. Miyake, Y. Iyechika, and T. Maeda, “Fabrication and characterization of low defect density GaN using facet-controlled epitaxial lateral overgrowth (FACELO),” J. Cryst. Growth, vol. 221, pp. 316–326, 2000.
[86] C. H. Ko, Y. K. Su, S. J. Chang, T. Y. Tsai, T. M. Kuan, W. H. Lan, J. C. Lin, “Two-step epitaxial lateral overgrowth of GaN”, Materials Chemistry and Physics, 82, pp. 55-60, 2003.
[87] T. S. Zheleva, O. H. Nam, M. D. Bremser, and R. F. Davis, “Dislocation density reduction via lateral epitaxy in selectively grown GaN structures,” Appl. Phys. Lett., vol. 71, pp. 2472–2474, 1997.
[88] X. Zhang, R. R. Li, P. D. Dapkus, and D. H. Rich, “Direct lateral epitaxy overgrowth of GaN on sapphire substratesbased on a sparse GaN nucleation technique,” Appl. Phys. Lett., vol. 77, pp. 2213–2215, 2000.
[89] H. S. Cheong, M. K. Yoo, H. G. Kim, S. J. Bae, C. S. Kim, C.-H. Hong, J. H. Baek, H. J. Kim, Y. M. Yu , and H. K. Cho, “Direct heteroepitaxial lateral overgrowth of GaN on stripe-patterned sapphire substrates with very thin SiO2 masks ,” phys. stat. sol. (b) vol. 241, pp. 2763–2766, 2004.
[90] J. J. Chen, Y. K. Su, C. L. Lin, S. M. Chen, W. L. Li, and C. C. Kao, “Enhanced output power of GaN-based LEDs with nano-patterned sapphire substrates,” IEEE Photon. Technol. Lett., vol. 20, pp. 1193–1195, 2008.
[91] C. C. Kao, Y. K. Su, W. L. Li, and J. J. Chen, “The Aspect Ratio Effects on the Performances of GaN-Based Light-Emitting Diodes with Nano-Patterned Sapphire Substrates,” Appl. Phys. Lett., vol. 97, pp. 023111-1–3, 2010.
[92] H. C. Lin, H. H. Liu, G. Y. Lee, J. I. Chyi, C. M. Lu, C. W. Chao, T. C. Wang, C. J. Chang, and S. W. S. Chi, “Effects of Lens Shape on GaN Grown on Microlens Patterned Sapphire Substrates by Metallorganic Chemical VaporDeposition,” J. Electrochem. Soc., vol. 157, pp. H304–H307, 2010.
[93] 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 SiO2 /polystyrene microlens arrays,” Appl. Phys. Lett., vol. 91, pp. 221107-1-221107-3, 2007.
[94] 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. 91, pp. 13747-13757, 2009.
[95] J. J. Wierer, A. David and M. M. Megens, “III-nitride photonic-crystal light-emitting diodes with high extraction efficiency,” Nature Photon., vol. 3, pp. 163–169, 2009.
[96] D. H. Jang, J. I. Shim, and D. S. Shin, “Enhancement of Light Extraction Efficiency Using Lozenge-Shaped GaN-Based Light-Emitting Diodes,” IEEE Photon. Technol. Lett., vol. 21, pp. 760–762, 2008.
[97] C. C. Yang, C. F. Lin, R. H. Jiang, H. C. Liu, C. M. Lin, C. Y. Chang, D. S. Wuu, H. C. Kuo, and S. C. Wang, “Wet Mesa Etching Process in InGaN-based Light Emitting Diodes,” Electrochem. Solid-State Lett., vol. 11, pp. H169-H172, 2008.
[98] D. S. Kuo, S. J. Chang, T. K. Ko, C. F. Shen, S. J. Hon, and S. C. Hung, “Nitride-Based LEDs With Phosphoric Acid Etched Undercut Sidewalls,” IEEE Photon. Technol. Lett., vol. 21, pp.510–512, 2008.
[99] M. H. Lo, P. M. Tu, C. H. Wang, C. W. Hung, S. C. Hsu, Y. J. Cheng, H. C. Kuo, H. W. Zan, S. C. Wang, C. Y. Chang, and S. C. Huang, “High efficiency light emitting diode with anisotropically etched GaN-sapphire interface,” Appl. Phys. Lett., vol. 95, pp. 041109-1-041109-3, 2009.
[100] C. C. Yang, C. F. Lin, H. C. Liu, C. M. Lin, R. H. Jiang, K. T. Chen, and J. F. Chien, “Higher Light-Extraction Efficiency of Nitride-Based Light-Emitting Diodes with Hexagonal Inverted Pyramids Structures,” J. Electrochem. Soc., vol. 156, pp. H316–H319, 2009.
[101] K. T. Chen, W. C. Huang, T. H. Hsieh, C. H. Hsieh, and C. F. Lin, “InGaN light emitting solar cells with a roughened N-face GaN surface through a laser decomposition process,” Optics Express., vol. 18, pp. 23406-23412, 2010.
[102] C. H. Chiu, Z. Y. Li, C. L.Chao, M. H. Lo, H. C. Kuo, P. C. Yu, T. C. Lu, S. C. Wang, K. M. Lau, and S. J. Cheng, “Efficiency enhancement of UV/blue light emitting diodes via nanoscaled epitaxial lateralovergrowth of GaN on a SiO2 nanorod-array patterned sapphire substrate,” J. Cryst. Growth., vol. 310, pp. 5170-5174, 2008.
[103] T. Kozawa, T. Kachi, H. Kano, H. Nagase, N. Koide, and K. Manabe, “Thermal stress in GaN epitaxial layers grown on sapphire substrates,” J. Appl. Phys., vol. 77, pp. 4389-4392, 1995.
[104] T. Takeuchi, S. Sota, M. Katsuragawa, M. Komori, H. Takeuchi, H. Amano and I. Akasaki, “Quantum-confined Stark effect due to piezoelectric fields in GaInN strained quantum wells,” Jpn. J. Appl. Phys., vol. 36, pp. 382-385, 1997.
[105] S. F. Chichibu, A. C. Abare, M. S. Minsky, S. Keller, S. B. Fleischer, J. E. Bowers, E. Hu, U. K. Mishra, L. A. Coldren, S. P. DenBaars and T. Sota, “Effective band gap inhomogeneity and piezoelectric field in InGaN/GaN multiquantum well structures,” Appl. Phys. Lett., vol. 73, pp. 2006-2008, 2008.
[106] H. Schift, “Nanoimprint lithography: An old story in modern times? A review,” J. Vac. Sci. Technol. B., vol. 26, pp. 458–480, 2008.
[107] S. Y. Chou, P. R. Krauss, and P. J. Renstrom, “Imprint Lithography with 25- Nanometer Resolution,” Science., vol. 272, pp. 85-87, 1996.
[108] S. Y. Chou, P. R. Krauss, and P. J. Renstrom, “Nanoimprint lithography,” J. Vac. Sci. Technol. B., vol. 14, pp. 4129–4133, 1996.
[109] T. Balla, S. M. Spearing and A. Monk, “An assessment of the process capabilities of nanoimprint lithography,” J. Phys. D: Appl. Phys., vol. 41, pp. 174001-1–174001-10, 2008.
[110] J. Haisma, M. Verheijen, V. D. Heuvel and J. V. D. Berg, “Mold-assisted nanolithography: A process for reliable pattern replication,” J. Vac. Sci. Technol. B vol. 14, pp. 4124-4128, 1996.
[111] U. Plachetka, M. Bendera, A. Fuchsa, B. Vratzova, T. Glinsnerb, F. Lindnerb and H. Kurz, “Wafer scale patterning by soft UV-Nanoimprint Lithography,” J. Vac. Sci. Technol. B vol. 73-74, pp. 167-171, 2004.
[112] A. P. Quist, E. Pavlovic, and S. Oscarsson, “Recent advances in microcontact printing,” Anal. Bioanal. Chem., vol. 381, pp. 591-600, 2005.
[113] Y. Xia and G. M. Whitesides, “Soft Lithography,” Annu. Rev. Mater. Sci., vol. 28, pp. 153-184, 1998.
[114] Y. Sun, Y. H. Cho, H. M. Kim and T. W. Kang, “High efficiency and brightness of blue light emission from dislocation-free InGaN/GaN quantum well nanorod arrays,” Appl. Phys. Lett., vol. 87, pp. 093115-1-093115-3, 2005.
[115] D. S. Wuu, H. W. Wu, S. T. Chen, T. Y. Tsai, X. Zheng, R. H. Horng, “Defect reduction of laterally regrown GaN on GaN/patterned sapphire substrates ,” J. Cryst. Growth., vol. 311, pp. 3063–3066, 2009.
[116] J. H. Cheng, Y. C. S. Wu, W. C. Liao, and B. W. Lin, “Improved crystal quality and performance of GaN-based light-emitting diodes by decreasing the slanted angle of patterned sapphire,” Appl. Phys. Lett., vol. 96, pp. 051109-1-051109-3, 2010.
[117] H. W. Huang, J. K. Huang, S. Y. Kuo, K. Y. Lee, and H. C. Kuo, “High extraction efficiency GaN-based light-emitting diodes on embedded SiO2 nanorod array and nanoscale patterned sapphire substrate,” Appl. Phys. Lett., vol. 96, pp. 263115-1-263115-3, 2010.
[118] J. J. Chen, Y. K. Su, C. L. Lin, S. M. Chen, W. L. Li, and C. C. Kao, “Enhanced output power of GaN-based LEDs with nano-patterned sapphire substrates,” IEEE Photon. Technol. Lett., vol. 20, pp. 1193–1195, 2008.
[119] H. M. Lo, Y. T. Hsieh, S. C. Shei, Y. C. Lee, X. F. Zeng, W. Y. Weng, N. M. Lin, and S. J. Chang, Y. T. Hsieh, and Y. C. Lee, “AlGaInP LEDs Prepared by Contact-Transferred and Mask-Embedded Lithography,” IEEE J. Quantum Electron., vol. 46, pp.1834-1839, 2010.
[120] Y. T. Hsieh, and Y. C. Lee, “Direct metal contact printing lithography for patterning sub-micrometer surface structures on a sapphire substrate,” J. Micromech. Microeng., vol. 21, pp. 015001-1-015001-6, 2011.
[121] B.S. Tan, S. Yuan, X.J. Kang, “Performance enhancement of InGaN light-emitting diodes by laser lift-off and transferfrom sapphire to copper substrate,” Appl. Phys. Lett., vol. 84, pp. 2757-2759, 2004.
[122] S. H. Huang, R. H. Horng, S. C. Hsu, T. Y. Chen, and D. S.Wuu, “Surface texturing for wafer-bonded vertical-typed GaN/mirror/Si lightemitting diodes,” Jpn. J. Appl. Phys., vol. 44, pp. 3028–3031, 2005.
[123] C.Y. Hu, X.N. Kang, T. Dai, M.J. Wang, Z.X. Qin, Z.Z. Chen, H. Yang, B. Shen, G.Y. Zhang, “Influence of laser lift-off process on the performances and largearea light-emitting diodes,” Journal of Crystal Growth, vol. 298, pp. 719-721, 2007.
[124] C. L. Chang, Y. C. Chuang, and C. Y. Liu, “Ag/Au Diffusion Wafer Bonding for Thin-GaN LED Fabrication,” Electrochem. Solid-State Lett., vol. 10, pp. H344-H346, 2007.
[125] P. Perlin, C. Kisielowski, V. Iota, B. A. Weinstein, L. Mattos, N. A. Shapiro, J. Kruger, E. R. Weber, and J. Yang, “InGaN/GaN quantum wells studied by high pressure, variable temperature, and excitation power spectroscopy,” Appl. Phys. Lett., vol. 73, pp. 2778-2780, 1998.
[126] S. Wetzel; S. Yamaguchi; H. Sakai; H. Amano; I. Akasaki, Y. Yamaoka, Y. Kaneko, S. Takeuchi, S. Nakagawa, and N. Yamada, “Determination of piezoelectric fields in strained GaInN quantum wells using the quantum-confined Stark effect”, Appl. Phys. Lett., vol. 73, pp. 1691-1964, 1998
[127] Y. S. Wu, J. H. Cheng, W. C. Peng, H. Ouyang, “Effects of laser sources on the reverse-bias leakage of laser lift-off GaN-based light-emitting diodes,” Appl. Phys. Lett., vol. 90, pp. 251110-1-251110-3, 2007.
[128] J. H. Cheng, Y. C. S. Wu, W. C. Peng, and H. Ouyang, “Effects of Laser Sources on Damage Mechanisms and Reverse-Bias Leakages of Laser Lift-Off GaN-Based LEDs,” J. Electrochem. Soc., vol. 156, pp. H640–H643, 2009.
[129] T. Afentakis, M. Hatalis, A. T. Voutsas, and J. Hartzell, “Design and fabrication of high-performance polycrystalline silicon thin-film transistor circuits on flexible steel foils,” IEEE Trans. Electron. Dev., vol. 53, pp. 815–822, 2006.
[130] D. D. Roover, A. E. Naeini, and J. L. Ebert, “Chemical Mechanical Planarization Controller,” U.S. Patent 7,050,880 B2, May 23, 2006.
[131] V. Yu. Davydov, Yu. E. Kitaev, I. N. Goncharuk, A. N. Smirnov, J. Graul, O. Semchinova, D. Uffmann, M. B.Smirnov, A. P. Mirgorodsky, and R. A. Evarestov, “Phonon dispersion and Raman scattering in hexagonal GaN and AlN,” Phys. Rev. B, vol. 58, pp. 12899–12907, 1998.