Advertisement

The Light Extraction Efficiency for DUV LEDs

  • Zi-Hui ZhangEmail author
  • Chunshuang Chu
  • Kangkai Tian
  • Yonghui Zhang
Chapter
Part of the SpringerBriefs in Applied Sciences and Technology book series (BRIEFSAPPLSCIENCES)

Abstract

DUV LEDs have very low light extraction efficiency (LEE), which is caused by the unique optical polarization and the optically absorptive semiconductor and metal layers. This chapter reviews and analyzes the approaches that have ever been used to improve the LEE. This chapter also points out that, the removal of the p-GaN layer can yield a high LEE without guaranteeing the enhanced wall plug efficiency in the same time. Thus, even more effort shall be made to achieve excellent ohmic contact for DUV LEDs.

References

  1. 1.
    Shatalov M, Sun W, Jain R, Lunev A, Hu X, Dobrinsky A, Bilenko Y, Yang J, Garrett GA, Rodak LE, Wraback M, Shur M, Gaska R (2014) High power AlGaN ultraviolet light emitters. Semicond Sci Technol 29(8):084007.  https://doi.org/10.1088/0268-1242/29/8/084007CrossRefGoogle Scholar
  2. 2.
    Lobo N, Rodriguez H, Knauer A, Hoppe M, Einfeldt S, Vogt P, Weyers M, Kneissl M (2010) Enhancement of light extraction in ultraviolet light-emitting diodes using nanopixel contact design with Al reflector. Appl Phys Lett 96(8):081109.  https://doi.org/10.1063/1.3334721CrossRefGoogle Scholar
  3. 3.
    Inazu T, Fukahori S, Pernot C, Kim MH, Fujita T, Nagasawa Y, Hirano A, Ippommatsu M, Iwaya M, Takeuchi T, Kamiyama S, Yamaguchi M, Honda Y, Amano H, Akasaki I (2011) Improvement of light extraction efficiency for AlGaN-based deep ultraviolet light-emitting diodes. Jpn J Appl Phys 50:122101.  https://doi.org/10.1143/jjap.50.122101CrossRefGoogle Scholar
  4. 4.
    Zhmakin AI (2011) Enhancement of light extraction from light emitting diodes. Phys Rep-Rev Sect Phys Lett 498(4–5):189–241.  https://doi.org/10.1016/j.physrep.2010.11.001CrossRefGoogle Scholar
  5. 5.
    Kim M, Fujita T, Fukahori S, Inazu T, Pernot C, Nagasawa Y, Hirano A, Ippommatsu M, Iwaya M, Takeuchi T, Kamiyama S, Yamaguchi M, Honda Y, Amano H, Akasaki I (2011) AlGaN-based deep ultraviolet light-emitting diodes fabricated on patterned sapphire substrates. Appl Phys Express 4(9):092102.  https://doi.org/10.1143/APEX.4.092102CrossRefGoogle Scholar
  6. 6.
    Dong P, Yan J, Wang J, Zhang Y, Geng C, Wei T, Cong P, Zhang Y, Zeng J, Tian Y, Sun L, Yan Q, Li J, Fan S, Qin Z (2013) 282-nm AlGaN-based deep ultraviolet light-emitting diodes with improved performance on nano-patterned sapphire substrates. Appl Phys Lett 102(24):241113.  https://doi.org/10.1063/1.4812237CrossRefGoogle Scholar
  7. 7.
    Adivarahan V, Fareed Q, Islam M, Katona T, Krishnan B, Khan A (2007) Robust 290 nm emission light emitting diodes over pulsed laterally overgrown AlN. Jpn J Appl Phys Part 2-Lett & Express Lett 46(36):L877–L879, Oct 2007.  https://doi.org/10.1143/jjap.46.l877CrossRefGoogle Scholar
  8. 8.
    Lee D, Lee JW, Jang J, Shin IS, Jin L, Park JH, Kim J, Lee J, Noh HS, Kim YI, Park Y, Lee GD, Kim JK, Yoon E (2017) Improved performance of AlGaN-based deep ultraviolet light-emitting diodes with nano-patterned AlN/sapphire substrates. Appl Phys Lett 110(19):191103.  https://doi.org/10.1063/1.4983283CrossRefGoogle Scholar
  9. 9.
    Inoue S-I, Naoki T, Kinoshita T, Obata T, Yanagi H (2015) Light extraction enhancement of 265 nm deep-ultraviolet light-emitting diodes with over 90 mW output power via an AlN hybrid nanostructure. Appl Phys Lett 106(13):131104.  https://doi.org/10.1063/1.4915255CrossRefGoogle Scholar
  10. 10.
    Liang R, Dai J, Xu L, He J, Wang S, Peng Y, Wang H, Ye L, Chen C (2018) High light extraction efficiency of deep ultraviolet LEDs enhanced using nanolens arrays. IEEE Trans Electron Devices 65(6):2498–2503.  https://doi.org/10.1109/ted.2018.2823742CrossRefGoogle Scholar
  11. 11.
    Khizar M, Fan ZY, Kim KH, Lin JY, Jiang HX (2005) Nitride deep-ultraviolet light-emitting diodes with microlens array. Appl Phys Lett 86(17):173504.  https://doi.org/10.1063/1.1914960CrossRefGoogle Scholar
  12. 12.
    Lachab M, Asif F, Zhang B, Ahmad I, Heidari A, Fareed Q, Adivarahan V, Khan A (2013) Enhancement of light extraction efficiency in sub-300 nm nitride thin-film flip-chip light-emitting diodes. Solid-State Electron 89:156–160.  https://doi.org/10.1016/j.sse.2013.07.010CrossRefGoogle Scholar
  13. 13.
    Guo YA, Zhang Y, Yan JC, Xie HZ, Liu L, Chen X, Hou MJ, Qin ZX, Wang JX, Li JM (2017) Light extraction enhancement of AlGaN-based ultraviolet light-emitting diodes by substrate sidewall roughening. Appl Phys Lett 111(1):011102.  https://doi.org/10.1063/1.4991664CrossRefGoogle Scholar
  14. 14.
    Wierer JJ Jr, Allerman AA, Montano I, Moseley MW (2014) Influence of optical polarization on the improvement of light extraction efficiency from reflective scattering structures in AlGaN ultraviolet light-emitting diodes. Appl Phys Lett 105(6):061106.  https://doi.org/10.1063/1.4892974CrossRefGoogle Scholar
  15. 15.
    Kim DY, Park JH, Lee JW, Hwang S, Oh SJ, Kim J, Sone C, Schubert EF, Kim JK (2015) Overcoming the fundamental light-extraction efficiency limitations of deep ultraviolet light-emitting diodes by utilizing transverse-magnetic-dominant emission. Light-Sci Appl 4(4):e263–e263.  https://doi.org/10.1038/lsa.2015.36CrossRefGoogle Scholar
  16. 16.
    Lee JW, Park JH, Kim DY, Schubert EF, Kim J, Lee J, Kim YI, Park Y, Kim JK (2016) Arrays of truncated cone AlGaN deep-ultraviolet light-emitting diodes facilitating efficient outcoupling of in-plane emission. Acs Photonics 3(11):2030–2034.  https://doi.org/10.1021/acsphotonics.6b00572CrossRefGoogle Scholar
  17. 17.
    Lee JW, Kim DY, Park JH, Schubert EF, Kim J, Lee J, Kim YI, Park Y, Kim JK (2016) An elegant route to overcome fundamentally-limited light extraction in AlGaN deep-ultraviolet light-emitting diodes: Preferential outcoupling of strong in-plane emission. Sci Rep 6(1):22537.  https://doi.org/10.1038/srep22537CrossRefGoogle Scholar
  18. 18.
    Guo YN, Zhang Y, Yan JC, Chen X, Zhang S, Xie HZ, Liu P, Zhu HF, Wang JX, Li JM (2017) Sapphire substrate sidewall shaping of deep ultraviolet light-emitting diodes by picosecond laser multiple scribing. Appl Phys Express 10(6):062101.  https://doi.org/10.7567/APEX.10.062101CrossRefGoogle Scholar
  19. 19.
    Chen Q, Zhang H, Dai J, Zhang S, Wang S, He J, Liang R, Zhang Z-H, Chen C (2018) Enhanced the optical power of AlGaN-based deep ultraviolet light-emitting diode by optimizing mesa sidewall angle. IEEE Photonics J 10(4):6100807.  https://doi.org/10.1109/JPHOT.2018.2850038CrossRefGoogle Scholar
  20. 20.
    Zhang Y, Meng R, Zhang Z-H, Shi Q, Li L, Liu G, Bi W (2017) Effects of inclined sidewall structure with bottom metal air cavity on the light extraction efficiency for AlGaN-based deep ultraviolet light-emitting diodes. IEEE Photonics J 9(5):1600709.  https://doi.org/10.1109/JPHOT.2017.2736642CrossRefGoogle Scholar
  21. 21.
    Zhang Y, Zheng Y, Meng R, Sun C, Tian K, Geng C, Zhang Z-H, Liu G, Bi W (2018) Enhancing both TM- and TE-polarized light extraction efficiency of AlGaN-based deep ultraviolet light-emitting diode via air cavity extractor with vertical sidewall. IEEE Photonics J 10(4):8200809.  https://doi.org/10.1109/JPHOT.2018.2849747CrossRefGoogle Scholar
  22. 22.
    Dong P, Yan JC, Zhang Y, Wang JX, Geng C, Zheng HY, Wei XC, Yan QF, Li JM (2014) Optical properties of nanopillar AlGaN/GaN MQWs for ultraviolet light-emitting diodes. Opt Express 22(5):A320–A327.  https://doi.org/10.1364/OE.22.00A320CrossRefGoogle Scholar
  23. 23.
    Ryu HY (2014) Large enhancement of light extraction efficiency in AlGaN-based nanorod ultraviolet light-emitting diode structures. Nanoscale Res Lett 9(1):58.  https://doi.org/10.1186/1556-276X-9-58CrossRefGoogle Scholar
  24. 24.
    Ooi YK, Liu C, Zhang J (2017) Analysis of polarization-dependent light extraction and effect of passivation layer for 230-nm AlGaN nanowire light-emitting diodes. IEEE Photonics J 9(4):4501712.  https://doi.org/10.1109/JPHOT.2017.2710325CrossRefGoogle Scholar
  25. 25.
    Zhao S, Sadaf SM, Vanka S, Wang Y, Rashid R, Mi Z (2016) Sub-milliwatt AlGaN nanowire tunnel junction deep ultraviolet light emitting diodes on silicon operating at 242 nm. Appl Phys Lett 109(20):325.  https://doi.org/10.1063/1.4967837CrossRefGoogle Scholar

Copyright information

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2019

Authors and Affiliations

  • Zi-Hui Zhang
    • 1
    Email author
  • Chunshuang Chu
    • 1
  • Kangkai Tian
    • 1
  • Yonghui Zhang
    • 1
  1. 1.School of Electronics and Information Engineering, Institute of Micro-Nano Photoelectron and Electromagnetic Technology InnovationHebei University of TechnologyTianjinChina

Personalised recommendations