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2022 Vol.32, Issue 6 Preview Page
Improving the Light Extraction Efficiency of GRIN Coatings Pillar Light Emitting Diodes
War War Moe†
,
Mg Aye
,
Tin Tin Hla
Department of Electronic Engineering, Mandalay Technological University (MTU), Myanmar
†Corresponding author E-Mail : moewintwar@gmail.com (W. W. Moe, MTU, Myanmar)
June 2022. pp. 293-300
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Abstract

This study investigated a graded-refractive-index (GRIN) coating pattern capable of improving the light extraction efficiency of GaN light-emitting diodes (LEDs). The planar LEDs had total internal reflection thanks to the large difference in refractive index between the LED semiconductor and the surrounding medium (air). The main goal of this paper was to reduce the trapped light inside the LED by controlling the refractive index using various compositions of (TiO2)x(SiO2)1−x in GRIN LEDs consisting of five dielectric layers. Several types of multilayer LEDs were simulated and it was determined the transmittance value of the LEDs with many layers was greater than the LEDs with less layers. Then, the specific ranges of incident angles of the individual layers which depend on the refractive index were evaluated. According to theoretical calculations, the light extraction efficiency (LEE) of the five-layer GRIN is 25.29 %, 28.54 % and 30.22 %, respectively. Consequently, the five-layer GRIN LEDs patterned enhancement outcome LEE over the reference planar LEDs. The results suggest the increased light extraction efficiency is related to the loss of Fresnel transmission and the release of the light mode trapped inside the LED chip by the graded-refractive-index.

Keywords
graded-refractive-index
total internal reflection
light extraction efficiency
References
1.
E. F. Schubert and J. K. Kim, Science, 308, 1274 (2005). 10.1126/science.110871215919985
2.
P. Zhu, Mater. Res. Express, 2, 096202 (2015). 10.1088/2053-1591/2/9/096202
3.
Y. Zho, H. Li, X. Xu, M. Chen, D. Xiong, Y. Long, S. Chen, R. Li, Z. Liu, J. Non-Cryst. Solids., 471, 215 (2017). 10.1016/j.jnoncrysol.2017.05.042
4.
J. K. Kim, A. N. Noemaun, F. W. Mont, D. Meyaard, E. F. Schubert, D. J. Poxson, H. Kim, C. Sone and Y. Park, Appl. Phys. Lett., 93, 221111 (2008). 10.1063/1.3041644
5.
A. N . Noemaun, F. W. M ont, G. B. L in, J. C ho, E . F. Schubert, G. B. Kim, C. Sone and J. K. Kim, J. Appl. Phys., 110, 054510 (2011). 10.1063/1.3632072
6.
M. Ma, J. Cho, E. F. Schubert, Y. Park, G. B. Kim and C. Sone, Appl. Phys. Lett., 101, 141105 (2012). 10.1063/1.4756797
7.
M. Ma, J. Cho, E. F. Schubert, G. B. Kim and C. Sone, J. Mater. Chem. C, 1, 8134 (2013). 10.1039/c3tc31620c
8.
M. Ma, A. N. Noemaun, J. Cho, E. F. Schubert, G. B. Kim and C. Sone, Opt. Express, 20, 16677 (2012). 10.1364/OE.20.016677
9.
S. O. Kasap, Principles of electronic Materials and devices, 4th Ed, p. 7, McGraw-Hill Education, University of Saskatchewan, Canada (2018).
10.
S. Sharma, P. B. Patel, R. S. Patel and J. J. Vora, E-J. Chem., 4, 343 (2007). 10.1155/2007/485378
11.
Z. B. B. Oral, Acta Phys. Pol. A, 127, 1314-1316(2015). 10.12693/APhysPolA.127.1314
12.
A.N. Noemaun, F. W. Mont, J. Cho and E. F. Schubert, J. Vac. Sci. Technol. A, 29, 051302 (2011). 10.1116/1.3620494
13.
B. K. Lee, K. S. Goh, Y. L. Chin and C. W. Tan, U.S. Patent 6717362, B1 (2004).
14.
F. W. Mont, J. K. Kim, M. F. Schubert, E. F. Schubert and R. W. Siegel, J. Appl. Phys., 103, 083120 (2008). 10.1063/1.2903484
15.
F. W. Mont, J. K. Kim, M. F. Schubert, E. F. Schubert and R. W. Siegel, Proc. of SPIE., 6486, 64861C (2007).
16.
W. W. Moe, M. Aye and T. T. Hla, “Comparison of Light Extracted Angles within Two-Layers and Three-Layers GRIN Pillar LEDs”, Proceedings of the 9th Universal Academic Cluster International Online Conference, Bangkok, 28 October 2021, p. 244-255.
17.
W. W. Moe, M. Aye, T. T. Hla, “Analysis on Graded- Refractive-Index Micropillars with Molar Ratio of GaInN Light Emitting Diodes”, Proceedings of the 9th Universal Academic Cluster International Online Conference, Bangkok, 28 October 2021, p. 256-269.
18.
M. Ma, F. W. Mont, X. Yan, J. Cho, E. F. Schubert, Gi. B. Kim and C. Sone, Opt. Express, 19, A1135 (2011). 10.1364/OE.19.0A113521935256
19.
M. R. Krames, O. B. Shchekin, R. M-Mach, G. O. Mueller, L. Zhou, G. Harbers and M. G, Craford, J. Disp. Technol., 3, 160 (2007). 10.1109/JDT.2007.895339
Information
  • Publisher :Materials Research Society of Korea
  • Publisher(Ko) :한국재료학회
  • Journal Title :Korean Journal of Materials Research
  • Journal Title(Ko) :한국재료학회지
  • Volume : 32
  • No :6
  • Pages :293-300
  • Received Date : 2022-05-26
  • Revised Date : 2022-05-26
  • Accepted Date : 2022-06-15
  • DOI :https://doi.org/10.3740/MRSK.2022.32.6.293
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