Open AccessImproved efficiency of InGaN/GaN light-emitting diodes with perpendicular magnetic field gradients
Author(s) -
Jae-Bok Han,
JaeJoon Kim,
YoungChul Leem,
SangJo Kim,
Wonyoung Kwak,
WooLim Jeong,
Beongki Cho,
Dong-Seon Lee,
Seong-Ju Park
Publication year - 2019
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.27.036708
Subject(s) - materials science , light emitting diode , optoelectronics , ferromagnetism , magnetic field , diode , optics , photoluminescence , ohmic contact , condensed matter physics , physics , nanotechnology , layer (electronics) , quantum mechanics
The effect of magnetic fields on the optical output power of flip-chip light-emitting diodes (LEDs) with InGaN/GaN multiple quantum wells (MQWs) was investigated. Films and circular disks comprising ferromagnetic cobalt/platinum (Co/Pt) multilayers were deposited on a p-ohmic reflector to apply magnetic fields in the direction perpendicular to the MQWs of the LEDs. At an injection current of 20 mA, the ferromagnetic Co/Pt multilayer film increased the optical output power of the LED by 20% compared to an LED without a ferromagnetic Co/Pt multilayer. Furthermore, the optical output power of the LED with circular disks was 40% higher at 20 mA than the output of the LED with a film. The increase of the optical output power of the LEDs featuring ferromagnetic Co/Pt multilayers is attributed to the magnetic field gradient in the MQWs, which increases the carrier path in the MQWs. The time-resolved photoluminescence measurement indicates that the improvement of optical output power is owing to an enhanced radiative recombination rate of the carriers in the MQWs as a result of the magnetic field gradient from the ferromagnetic Co/Pt multilayer.