Open AccessLight output performance of red AlGaInP-based light emitting diodes with different chip geometries and structures
Author(s) -
Jae Eung Oh,
Sang-Youl Lee,
Yong-Tae Moon,
Ji Hyung Moon,
Sung Soo Park,
Ki Yong Hong,
Ki-Young Song,
Chang Sik Oh,
JongIn Shim,
Hwan-Hee Jeong,
June-O Song,
Hiroshi Amano,
TaeYeon Seong
Publication year - 2018
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.011194
Subject(s) - light emitting diode , optoelectronics , quantum efficiency , cladding (metalworking) , materials science , diode , optics , chip , physics , telecommunications , computer science , metallurgy
We investigated the optical and electrical properties of red AlGaInP light-emitting diodes (LEDs) as functions of chip size, p-cladding layer thickness, and the number of multi-quantum wells (MQWs). External quantum efficiency (EQE) decreased with decreasing chip size. The ideality factor gradually increased from 1.47 to 1.95 as the chip size decreased from 350 μm to 15 μm. This indicates that the smaller LEDs experienced larger carrier loss due to Shockley-Read-Hall nonradiative recombination at sidewall defects. S parameter, defined as ∂lnL/∂lnI, increased with decreasing chip size. Simulations and experimental results showed that smaller LEDs with 5 pairs of MQWs had over 30% higher IQE at 5 A/cm 2 than the LED with 20 pairs of MQWs. These results show that the optimization of the number of QWs is needed to obtain maximum EQE of micro-LEDs.