Investigation of the efficiency-droop mechanism in vertical red light-emitting diodes using a dynamic measurement technique

J. W. Shi, F. M. Kuo, Che Wei Lin, Wei Chen, L. J. Yan, J. K. Sheu

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

The mechanism responsible for the efficiency droop in AlGaInP-based vertically structured red light-emitting diodes (LEDs) is investigated using dynamic measurement techniques. Short electrical pulses (∼100 ps) are pumped into this device and the output optical pulses probed using high-speed photoreceiver circuits. From this, the internal carrier dynamic inside the device can be investigated by use of the measured electrical-to-optical (E-O) impulse responses. Results show that the E-O responses measured under different bias currents are all invariant from room temperature to ∼100 °C. This is contrary to most results reported for AlGaInP-based red LEDs, which usually exhibit a shortening in the response time and degradation in output power with the increase of ambient temperature. According to the extracted fall-time constants of the E-O impulse responses, the origin of the efficiency droop in our vertical LED structure, which has good heat-sinking, is not due to thermally induced carrier leakage, but rather should be attributed to defect recombination and the saturation of defect/spontaneous recombination processes under low and high bias current, respectively.

Original languageEnglish
Article number5983398
Pages (from-to)1585-1587
Number of pages3
JournalIEEE Photonics Technology Letters
Volume23
Issue number21
DOIs
Publication statusPublished - 2011

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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