volume | PIER Journals

Abstract

In this work, we present a three-component hierarchical structure to simultaneously improve the red, green, and blue (RGB) light-extraction efficiency (LEE) of white light-emitting diodes (LEDs) based on color mixing method. With the help of 3D finite-difference time-domain (FDTD) simulations, the effects of the embedded photonic crystals (PhCs), the normal surface PhCs, and the nano-rods on the enhancement of RGB light extraction were investigated. The results were compared with those of the conventional planar LEDs and the normal surface PhCs LEDs over the whole visible spectrum. Results from the simulations demonstrated that the maximum LEE for the hierarchical structures LEDs gave 112%, 327%, and 284% RGB LEE enhancement, respectively, compared to that of the conventional planar LEDs, and achieved 104%, 191%, and 187% RGB LEE enhancement compared to that of LEDs with normal surface PhCs. The emission characteristics of the hierarchical structures LEDs were also revealed in detail by FDTD simulations. The results shown in this paper would do a favor for the design and fabrication of high efficiency LEDs.

1. Schubert, E. F., "Solid-state light sources getting smart," Science, Vol. 308, 1274-1278, 2005.
doi:10.1126/science.1108712

2. Krames, M. R., O. B. Shchekin, R. Mueller-Mach, G. O. Mueller, L. Zhou, G. Harbers, and M. George Craford, "Status and future of high-power light-emitting diodes for solid-state lighting," Journal of Display Technology, Vol. 3, 160-175, 2007.
doi:10.1109/JDT.2007.895339

3. Nishiura, S., S. Tanabe, K. Fujioka, and Y. Fujimoto, "Properties of transparent Ce:YAG ceramic phosphors for white LED," Optical Materials, Vol. 33, 688-691, 2011.
doi:10.1016/j.optmat.2010.06.005

4. Huang, C.-H. and T.-M. Chen, "A novel single-composition trichromatic white-light Ca3Y(GaO)3(BO3)4:Ce3+,Mn2+,Tb3+ phosphor for UV-light emitting diodes," The Journal of Physical Chemistry C, Vol. 115, 2349-2355, 2011.
doi:10.1021/jp107856d

5. Yang, C. J., C. S. Huang, C. W. Chen, and P. W. Chen, "The color mixing white-light LEDs," Applied Mechanics and Materials, Vol. 378, 440-443, 2013.
doi:10.4028/www.scientific.net/AMM.378.440

6. Yamada, M., Y. Narukawa, and T. Mukai, "Phosphor free high-luminous-efficiency white lightemitting diodes composed of InGaN multi-quantum well," Japanese Journal of Applied Physics, Vol. 41, L246-L248, 2002.
doi:10.1143/JJAP.41.L246

7. U. S. DOE "Solid-state lighting research and development: Multi year program plan,", 2011.

8. Kim, J. Y., O. Voznyy, D. Zhitomirsky, and E. H. Sargent, "25th Anniversary article: Colloidal quantum dot materials and devices: A quarter-century of advances," Advanced Materials, Vol. 25, 4986-5010, 2013.
doi:10.1002/adma.201301947

9. Kim, S., S. H. Im, and S.-W. Kim, "Performance of light-emitting-diode based on quantum dots," Nanoscale, Vol. 5, 5205, 2013.
doi:10.1039/c3nr00496a

10. Sun, C., Y. Zhang, Y. Wang, W. Liu, S. Kalytchuk, S. V. Kershaw, T. Zhang, X. Zhang, J. Zhao, W. W. Yu, and A. L. Rogach, "High color rendering index white light emitting diodes fabricated from a combination of carbon dots and zinc copper indium sulfide quantum dots," Applied Physics Letters, Vol. 104, 261106, 2014.
doi:10.1063/1.4886415

11. Dang, C., J. Lee, Y. Zhang, J. Han, C. Breen, J. S. Steckel, S. Coe-Sullivan, and A. Nurmikko, "A wafer-level integrated white-light-emitting diode incorporating colloidal quantum dots as a nanocomposite luminescent material," Advanced Materials, Vol. 24, 5915-5918, 2012.
doi:10.1002/adma.201202354

12. David, A., "Surface-roughened light-emitting diodes an accurate model," Journal of Display Technology, Vol. 9, 301-316, 2013.
doi:10.1109/JDT.2013.2240373

13. David, A., H. Benisty, and C. Weisbuch, "Photonic crystal light-emitting sources," Reports on Progress in Physics, Vol. 75, 126501, 2012.
doi:10.1088/0034-4885/75/12/126501

14. Xu, Z., L. Cao, Q. Tan, Q. He, and G. Jin, "Enhancement of the light output of light-emitting diode with double photonic crystals," Optics Communications, Vol. 278, 211-214, 2007.
doi:10.1016/j.optcom.2007.06.019

15. Chen, J.-Y., Y.-G. Li, J.-Y. Yeh, L.-W. Chen, and C.-C. Wang, "Design and modeling for enhancement of light extraction in light-emitting diodes with archimedean lattice photonic crystals," Progress In Electromagnetics Research B, Vol. 11, 265-279, 2009.
doi:10.2528/PIERB08112704

16. Kim, D., H. Lee, N. Cho, Y. Sung, and G. Yeom, "Effect of GaN microlens array on efficiency of GaN-based blue-light-emitting diodes," Japanese Journal of Applied Physics, Vol. 44, L18-L20, 2005.
doi:10.1143/JJAP.44.L18

17. Lee, C.-T. and T.-J. Wu, "Light distribution and light extraction improvement mechanisms of remote GaN-based white light-emitting-diodes using ZnO nanorod array," Journal of Luminescence, Vol. 137, 143-147, 2013.
doi:10.1016/j.jlumin.2012.12.057

18. Tsai, Y.-L., C.-Y. Liu, C. Krishnan, D.-W. Lin, Y.-C. Chu, T.-P. Chen, T.-L. Shen, T.-S. Kao, M. D. B. Charlton, P. Yu, C.-C. Lin, H.-C. Kuo, and J.-H. He, "Bridging the ‘green gap’ of LEDs: Giant light output enhancement and directional control of LEDs via embedded nano-void photonic crystals," Nanoscale, Vol. 8, 1192-1199, 2016.
doi:10.1039/C5NR05555E

19. Chen, Z.-X., Y. Ren, G.-H. Xiao, J.-T. Li, X. Chen, X.-H. Wang, C.-J. Jin, and B.-J. Zhang, "Enhancing light extraction of GaN-based blue light-emitting diodes by a tuned nanopillar array," Chinese Physics B, Vol. 23, 018502, 2014.
doi:10.1088/1674-1056/23/1/018502

20. Li, H., Z. Xu, B. Bao, and Y. Song, "Enhanced light extraction by heterostructure photonic crystals toward white-light-emission," Journal of Colloid and Interface Science, Vol. 465, 42-46, 2016.
doi:10.1016/j.jcis.2015.11.052

21. Gao, H., K. Li, F.-M. Kong, X.-L. Chen, and Z.-M. Zhang, "Improving light extraction efficiency of GaN-based LEDs by AlxGa1−xN confining layer and embedded photonic crystals," IEEE Journal of Selected Topics in Quantum Electronics, Vol. 18, 1650-1660, 2012.
doi:10.1109/JSTQE.2011.2175371

22. Yu, Z.-G., L.-X. Zhao, S.-C. Zhu, X.-C. Wei, X.-J. Sun, L. Liu, J.-X. Wang, and J.-M. Li, "Optimization of the nanopore depth to improve the electroluminescence for GaN-based nanoporous green LEDs," Materials Science in Semiconductor Processing, Vol. 33, 76-80, 2015.
doi:10.1016/j.mssp.2015.01.039

23. Chen, T. P., C. L. Yao, C. Y.Wu, J. H. Yeh, C. W. Wang, and M. H. Hsieh, "Recent developments in high brightness LEDs," International Society for Optics and Photonics, 2008.

24. Xu, F., Z. Lv, X. Lou, Y. Zhang, and Z. Zhang, "Nitrogen dioxide monitoring using a blue LED," Applied Optics, Vol. 47, 5337-5340, 2008.
doi:10.1364/AO.47.005337

25. Sacks, Z. S., D. M. Kingsland, R. Lee, and J.-F. Lee, "A perfectly matched anisotropic absorber for use as an absorbing boundary condition," IEEE Transactions on Antennas and Propagation, Vol. 43, 1460-1463, 1995.
doi:10.1109/8.477075

26. Kohler, U., D. J. As, B. S. Ttker, T. Frey, K. Lischka, J. Scheiner, and R. Goldhahn, "Optical constants of cubic GaN in the energy range of 1.5–3.7 eV," Journal of Applied Physics, Vol. 85, 404-407, 1999.
doi:10.1063/1.369398

27. Synowicki, R. A., "Spectroscopic ellipsometry characterization of indium tin oxide film microstructure and optical constants," Thin Solid Films, Vol. 313, 394-397, 1998.
doi:10.1016/S0040-6090(97)00853-5

28. Wiesmann, C., K. Bergenek, N. Linder, and U. T. Schwarz, "Photonic crystal LEDs — Designing light extraction," Laser & Photonics Review, Vol. 3, 262-286, 2009.
doi:10.1002/lpor.200810053

29. Zhmakin, A. I., "Enhancement of light extraction from light emitting diodes," Physics Reports, Vol. 498, 189-241, 2011.
doi:10.1016/j.physrep.2010.11.001

30. David, A., C. Meier, R. Sharma, F. S. Diana, S. P. DenBaars, E. Hu, S. Nakamura, C. Weisbuch, and H. Benisty, "Photonic bands in two-dimensionally patterned multimode GaN waveguides for light extraction," Applied Physics Letters, Vol. 87, 101107, 2005.
doi:10.1063/1.2039987

31. David, A., T. Fujii, R. Sharma, K. McGroddy, S. Nakamura, S. P. DenBaars, E. L. Hu, C. Weisbuch, and H. Benisty, "Photonic-crystal GaN light-emitting diodes with tailored guided modes distribution," Applied Physics Letters, Vol. 88, 061124, 2006.
doi:10.1063/1.2171475

32. Long, D. H., I.-K. Hwang, and S.-W. Ryu, "Design optimization of photonic crystal structure for improved light extraction of GaN LED," IEEE Journal of Selected Topics in Quantum Electronics, Vol. 15, 1257-1263, 2009.
doi:10.1109/JSTQE.2009.2014471

33. Shen, X. X., Y. Z. Ren, G. Y. Dong, X. Z. Wang, and Z. W. Zhou, "Optimization design of holographic photonic crystal for improved light extraction efficiency of GaN LED," Superlattices Microstructure, Vol. 64, 303-310, 2013.
doi:10.1016/j.spmi.2013.09.043

34. Fujita, M., "Simultaneous inhibition and redistribution of spontaneous light emission in photonic crystals," Science, Vol. 308, 1296-1298, 2005.
doi:10.1126/science.1110417

Dr. Meng Liu

Dr. Kang Li

Dr. Fanmin Kong

Dr. Jia Zhao

Dr. Chong-Jie Xu