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 language | English |
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Article number | 5983398 |
Pages (from-to) | 1585-1587 |
Number of pages | 3 |
Journal | IEEE Photonics Technology Letters |
Volume | 23 |
Issue number | 21 |
DOIs | |
State | Published - 2011 |
Keywords
- AlGaInP/GaP
- efficiency droop
- light-emitting-diodes (LEDs)