Electrical, optical and thermal degradation of high power GaN/InGaN light-emitting diodes

Jianzheng Hu, Lianqiao Yang, Moo Whan Shin

Research output: Contribution to journalArticlepeer-review

142 Citations (Scopus)


The degradation of high power GaN/InGaN blue light-emitting diodes (LEDs) was investigated by considering the electrical, optical and thermal ageing characteristics. The LED samples were stressed at the elevated temperature of 85 °C with an injection current of 350 mA. Changes in the tunnelling current and series resistance for the electrical characteristics and an initial increase followed by a gradual decrease for the optical power were observed. Variations of the thermal resistance in the chip and package were found to be 2 °C W-1 and 0.3 °C W-1, respectively. The responsible factors were proposed to be: (a) the dopant activation and changes of defects in the chip level; (b) the yellowing of the optical lens and structural degradations such as generating voids or delaminations in the package level. The changes in the electrical, optical and thermal characteristics were found to depend on and affect each other. The internal relationship for the characteristics of the three aspects was explained.

Original languageEnglish
Article number035107
JournalJournal of Physics D: Applied Physics
Issue number3
Publication statusPublished - 2008 Feb 7

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films


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