Linear cascade arrays of GaN-based green light-emitting diodes for high-speed and high-power performance

J. W. Shi, J. K. Sheu, C. K. Wang, C. C. Chen, C. H. Hsieh, J. I. Chyi, W. C. Lai

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


In the following study, we demonstrated linear cascade GaN-based light-emitting-diode (LED) arrays at a wavelength of approximately 520 nm. Experimental LEDs were analyzed with the goal to improve the output power and differential efficiency of a single LED. The study shows that using arrays with up to four LEDs connected in series, we can achieve four times the improvement in output power (differential quantum efficiency) under the same bias current as compared to a single LED apparatus. We have also measured the modulation-speed performance of experimental LEDs, and both devices exhibit similar 3-dB bandwidth (90 MHz) under the same bias currents. Experimental results indicate that the cascade connection offers the advantages of significantly enhanced external differential efficiency and provision of a method to use a constant-voltage power supply. The current crowding problem and resistance-capacitance-limited bandwidth degradation issues in a large active area LED can also be minimized using the connection demonstrated in our experiment.

Original languageEnglish
Pages (from-to)1368-1370
Number of pages3
JournalIEEE Photonics Technology Letters
Issue number18
Publication statusPublished - 2007 Sept 15

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering


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