Frontiers of Optoelectronics

, Volume 6, Issue 4, pp 429–434 | Cite as

Improvement of blue InGaN light-emitting diodes with gradually increased barrier heights from n- to p-layers

  • Wu Tian
  • Xiong Hui
  • Yang Li
  • Jiangnan Dai
  • Yanyan Fang
  • Zhihao Wu
  • Changqing Chen
Research Article


The advantages of blue InGaN light-emitting diodes (LED) with the active region of gradually increased barrier heights from n- to p-layers are studied. The energy band diagram, hole concentration, electrostatic field near the electron blocking layer (EBL), and the internal quantum efficiency (IQE) are investigated by Crosslight simulation program. The simulation results show that the structure with gradually increased barrier heights has better performance over the equal one, which can be attributed to the mitigated polarization effect near the interface of the last barrier/EBL due to less interface polarization charges. Moreover, reduced barrier height toward the n-layers is beneficial for holes injection and transportation in the active region. As a result, holes are injected into the active region more efficiently and distributed uniformly in the quantum wells, with which both the IQE and the total lighting power are increased. Although it can lead to the broadening of the spontaneous emission spectrum, the increase is slight such that it has little effect on the application in solid-state lighting.


InGaN light-emitting diodes (LED) polarization effect gradual barrier height 


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  1. 1.
    Oh J H, Oh J R, Park H K, Sung Y G, Do Y R. New paradigm of multi-chip white LEDs: combination of an InGaN blue LED and full down-converted phosphor-converted LEDs. Optics Express, 2011, 19(Suppl 3): A270–A279CrossRefGoogle Scholar
  2. 2.
    Li J, Lin J Y, Jiang H X. Growth of III-nitride photonic structures on large area silicon substrates. Applied Physics Letters, 2006, 88(17): 171909CrossRefGoogle Scholar
  3. 3.
    Liao C T, Tsai M C, Liou B T, Yen S H, Kuo Y K. Improvement in output power of a 460 nm InGaN light-emitting diode using staggered quantum well. Journal of Applied Physics, 2010, 108(6): 063107CrossRefGoogle Scholar
  4. 4.
    Gao H Y, Yan F W, Zhang Y, Li J M, Zeng Y P, Wang G H. Enhancement of the light output power of InGaN/GaN lightemitting diodes grown on pyramidal patterned sapphire substrates in the micro- and nanoscale. Journal of Applied Physics, 2008, 103(1): 014314CrossRefGoogle Scholar
  5. 5.
    Lee J H, Lee D Y, Oh B W, Lee J H. Comparison of InGaN-based LEDs grown on conventional sapphire and cone-shape-patterned sapphire substrate. IEEE Transactions on Electron Devices, 2010, 57(1): 157–163CrossRefGoogle Scholar
  6. 6.
    Tansu N, Mawst L J. Current injection efficiency of InGaAsN quantum-well lasers. Journal of Applied Physics, 2005, 97(5): 054502CrossRefGoogle Scholar
  7. 7.
    Choi S, Ji M H, Kim J, Kim H J, Satter M M, Yoder P D, Ryou J H, Dupuis R D, Fischer A M, Ponce F A. Efficiency droop due to electron spill-over and limited hole injection in III-nitride visible light-emitting diodes employing lattice-matched InAlN electron blocking layers. Applied Physics Letters, 2012, 101(16): 161110CrossRefGoogle Scholar
  8. 8.
    Hori A, Yasunaga D, Satake A, Fujiwara K. Temperature and injection current dependence of electroluminescence intensity in green and blue InGaN single-quantum-well light-emitting diodes. Journal of Applied Physics, 2003, 93(6): 3152–3157CrossRefGoogle Scholar
  9. 9.
    Wang C H, Chang S P, Ku P H, Li J C, Lan Y P, Lin C C, Yang H C, Kuo H C, Lu T C, Wang S C, Chang C Y. Hole transport improvement in InGaN/GaN light-emitting diodes by gradedcomposition multiple quantum barriers. Applied Physics Letters, 2011, 99(17): 171106CrossRefGoogle Scholar
  10. 10.
    Otsuji N, Fujiwara K, Sheu J K. Electroluminescence efficiency of blue InGaN/GaN quantum-well diodes with and without an n-InGaN electron reservoir layer. Journal of Applied Physics, 2006, 100(11): 113105CrossRefGoogle Scholar
  11. 11.
    Zhao H P, Liu G Y, Arif R A, Tansu N. Current injection efficiency induced efficiency-droop in InGaN quantum well light-emitting diodes. Solid-State Electronics, 2010, 54(10): 1119–1124CrossRefGoogle Scholar
  12. 12.
    Zhao H P, Liu G Y, Zhang J, Arif R A, Tansu R. Analysis of internal quantum efficiency and current injection efficiency in III-nitride light-emitting diodes. Journal of Display Technology, 2013, 9(4): 212–225CrossRefGoogle Scholar
  13. 13.
    Titkov I E, Sannikov D A, Park Y M, Son J K. Blue light emitting diode internal and injection efficiency. AIP Advances, 2012, 2(3): 032117CrossRefGoogle Scholar
  14. 14.
    Xu L F, Patel D, Menoni C S, Yeh J Y, Mawst L J, Tansu N. Experimental evidence of the impact of nitrogen on carrier capture and escape times in InGaAsN/GaAs single quantum well. IEEE Photonics Journal, 2012, 4(6): 2262–2271CrossRefGoogle Scholar
  15. 15.
    Tansu N, Mawst L J. The role of hole leakage in 1300-nm InGaAsN quantum-well lasers. Applied Physics Letters, 2003, 82(10): 1500–1502CrossRefGoogle Scholar
  16. 16.
    Chang J Y, Tsai M C, Kuo Y K. Advantages of blue InGaN lightemitting diodes with AlGaN barriers. Optics Letters, 2010, 35(9): 1368–1370CrossRefGoogle Scholar
  17. 17.
    Liu G Y, Zhang J, Tan C K, Tansu N. Efficiency-droop suppression by using large-bandgap AlGaInN thin barrier layers in InGaN quantum-well light-emitting diodes. IEEE Photonics Journal, 2013, 5(2): 2201011CrossRefGoogle Scholar
  18. 18.
    Delaney K T, Rinke P, Van de Walle C G. Auger recombination rates in nitrides from first principles. Applied Physics Letters, 2009, 94(19): 191109CrossRefGoogle Scholar
  19. 19.
    Tan C K, Zhang J, Li X H, Liu G Y, Tayo B O, Tansu N. Firstprinciple electronic properties of dilute-As GaNAs alloy for visible light emitters. Journal of Display Technology, 2013, 9(4): 272–279CrossRefGoogle Scholar
  20. 20.
    Kuo Y K, Chang J Y, Tsai M C. Enhancement in hole-injection efficiency of blue InGaN light-emitting diodes from reduced polarization by some specific designs for the electron blocking layer. Optics Letters, 2010, 35(19): 3285–3287CrossRefGoogle Scholar
  21. 21.
    Kuo Y K, Tsai M C, Yen S H. Numerical simulation of blue InGaN light-emitting diodes with polarization-matched AlGaInN electronblocking layer and barrier layer. Optics Communications, 2009, 282(21): 4252–4255CrossRefGoogle Scholar
  22. 22.
    Zhang Y Y, Yin Y A. Performance enhancement of blue lightemitting diodes with a special designed AlGaN/GaN superlattice electron-blocking layer. Applied Physics Letters, 2011, 99(22): 221103CrossRefGoogle Scholar
  23. 23.
    Vampola K J, Iza M, Keller S, DenBaars S P, Nakamura S. Measurement of electron overflow in 450 nm InGaN light-emitting diode structures. Applied Physics Letters, 2009, 94(6): 061116-1–061116-3CrossRefGoogle Scholar
  24. 24.
    Liou B T, Tsai M C, Liao C T, Yen S H, Kuo Y K. Numerical investigation of blue InGaN light-emitting diodes with staggered quantum wells. Proceedings of the Society for Photo-Instrumentation Engineers, 2009, 7211: 72111D-1–72111D-8Google Scholar
  25. 25.
    Jain S C, Willander M, Narayan J, Overstraeten R V. III-nitrides: growth, characterization, and properties. Journal of Applied Physics, 2000, 87(3): 965–1006CrossRefGoogle Scholar
  26. 26.
    Yen S H, Kuo Y K. Polarization-dependent optical characteristics of violet InGaN laser diodes. Journal of Applied Physics, 2008, 103(10): 103115-1–103115-6CrossRefGoogle Scholar
  27. 27.
    Kuo Y K, Yen S H, Wang Y W. Simulation of deep ultraviolet light-emitting diodes. Proceedings of the Society for Photo-Instrumentation Engineers, 2007, 6669: 66691JGoogle Scholar
  28. 28.
    Ambacher O, Foutz B, Smart J, Shealy J R, Weimann N G, Chu K, Murphy M, Sierakowski A J, Schaff WJ, Eastman L F, Dimitrov R, Mitchell A, Stutzmann M. Two dimensional electron gases induced by spontaneous and piezoelectric polarization in undoped and doped AlGaN/GaN hetero-structures. Journal of Applied Physics, 2000, 87(1): 334–344CrossRefGoogle Scholar
  29. 29.
    Fiorentini V, Bernardini F, Ambacher O. Evidence for nonlinear macroscopic polarization in III-V nitride alloy heterostructures. Applied Physics Letters, 2002, 80(7): 1204–1206CrossRefGoogle Scholar
  30. 30.
    Ridley B K, Schaff W J, Eastman L F. Theoretical model for polarization superlattices: Energy levels and intersubband transitions. Journal of Applied Physics, 2003, 94(6): 3972–3978CrossRefGoogle Scholar
  31. 31.
    Vurgaftman I, Meyer J R. Band parameters for nitrogen-containing semiconductors. Journal of Applied Physics, 2003, 94(6): 3675–3696CrossRefGoogle Scholar
  32. 32.
    Vurgaftman I, Meyer J R, Ram-Mohan L R. Band parameters for III-V compound semiconductors and their alloys. Journal of Applied Physics, 2001, 89(11): 5815–5875CrossRefGoogle Scholar
  33. 33.
    Chichibu S F, Abare A C, Minsky M S, Keller S, Fleischer S B, Bowers J E, Hu E, Mishra U K, Coldren L A, DenBaars S P, Sota T. Effective band gap inhomogeneity and piezoelectric field in InGaN/GaN multiquantum well structures. Applied Physics Letters, 1998, 73(14): 2006–2008CrossRefGoogle Scholar
  34. 34.
    Feezell D F, Speck J S, DenBaars S P, Nakamura S. Semipolar (20-2-1) InGaN/GaN light-emitting diodes for high-efficiency solidstate lighting. Journal of Display Technology, 2013, 9(4): 190–198CrossRefGoogle Scholar
  35. 35.
    Farrell R M, Haeger D A, Fujito K, DenBaars S P, Nakamura S, Speck J S. Morphological evolution of InGaN/GaN light-emitting diodes grown on free-standing m-plane GaN substrates. Journal of Applied Physics, 2013, 113(6): 063504CrossRefGoogle Scholar
  36. 36.
    Zhang J, Tansu N. Optical gain and laser characteristics of InGaN quantum wells on ternary InGaN substrates. IEEE Photonics Journal, 2013, 5(2): 2600111CrossRefGoogle Scholar
  37. 37.
    Zhao H P, Liu G Y, Zhang J, Poplawsky J D, Dierolf V, Tansu N. Approaches for high internal quantum efficiency green InGaN lightemitting diodes with large overlap quantum wells. Optics Express, 2011, 19(Suppl 4): A991–A1007CrossRefGoogle Scholar

Copyright information

© Higher Education Press and Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Wu Tian
    • 1
  • Xiong Hui
    • 1
  • Yang Li
    • 1
  • Jiangnan Dai
    • 1
  • Yanyan Fang
    • 1
  • Zhihao Wu
    • 1
  • Changqing Chen
    • 1
  1. 1.Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and TechnologyWuhanChina

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