By Topic

Investigation of the Efficiency-Droop Mechanism in Vertical Red Light-Emitting Diodes Using a Dynamic Measurement Technique

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

6 Author(s)
Shi, J.-W. ; Dept. of Electr. Eng., Nat. Central Univ., Jhongli, Taiwan ; Kuo, F.-M. ; Lin, C.-W. ; Wei Chen
more authors

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.

Published in:

Photonics Technology Letters, IEEE  (Volume:23 ,  Issue: 21 )