Optical Review

, Volume 16, Issue 2, pp 213–215 | Cite as

Electrical-optical analysis of a GaN/sapphire LED chip by considering the resistivity of the current-spreading layer

  • Jyh-Chen Chen
  • Gwo-Jiun Sheu
  • Farn-Shiun Hwu
  • Hsueh-I Chen
  • Jinn-Kong Sheu
  • Tsung-Xian Lee
  • Ching-Cherng Sun
Regular Papers

Abstract

The effects of current distribution in LED chips on the electrical potential and optical light extraction efficiency are investigated by a numerical simulation. The results show that when the resistivity of the current-spreading layer is decreased there is current-crowding near the n-contact. On the other hand, when the resistivity in the current-spreading layer increases, there is current-crowding near the p-contact. When the current is crowded near the n-contact due to less resistivity of the current-spreading layer, the input power is lower because of the smaller series resistance in the chip, and the light extraction efficiency is higher since the shadowing effect of the p-contact can be avoided. For Lp = 50 μm in this study, the light extraction efficiency at ρITO = 0.1 × 10−3 Ω·cm is 1.4 times better than that when Lp = 100 μm, even though the driving voltage is raised 1.02 times.

Keywords

current-spreading light-emitting diodes indium tin oxide numerical simulation light extraction efficiency 

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Copyright information

© The Optical Society of Japan 2009

Authors and Affiliations

  • Jyh-Chen Chen
    • 1
  • Gwo-Jiun Sheu
    • 1
  • Farn-Shiun Hwu
    • 1
    • 2
  • Hsueh-I Chen
    • 1
  • Jinn-Kong Sheu
    • 3
  • Tsung-Xian Lee
    • 4
  • Ching-Cherng Sun
    • 4
  1. 1.Department of Mechanical EngineeringNational Central UniversityJhongliTaiwan
  2. 2.Department of Mechanical EngineeringNanya Institute of TechnologyJhongliTaiwan
  3. 3.Institute of Electro-Optical Science and Engineering and Advanced Optoelectronic Technology CenterNational Cheng Kung UniversityTainanTaiwan
  4. 4.Institute of Optical SciencesNational Central UniversityJhongliTaiwan

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