Open AccessP-side-up thin-film AlGaInP-based light emitting diodes with direct ohmic contact of an ITO layer with a GaP window layer
Author(s) -
Mei-Chih Tseng,
Chi Lu Chen,
Nan Kai Lai,
Shih I. Chen,
Tzu Chieh Hsu,
Yu Ren Peng,
Ray–Hua Horng
Publication year - 2014
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.22.0a1862
Subject(s) - materials science , optoelectronics , ohmic contact , light emitting diode , indium tin oxide , layer (electronics) , wafer , optics , diode , thin film , composite material , nanotechnology , physics
A twice wafer-transfer technique can be used to fabricate high-brightness p-side-up thin-film AlGaInP-based light-emitting diodes (LEDs) with an indium-tin oxide (ITO) transparent conductive layer directly deposited on a GaP window layer, without using postannealing. The ITO layer can be used to improve light extraction, which enhances light output power. The p-side-up thin-film AlGaInP LED with an ITO layer exhibited excellent performance stability (e.g., emission wavelength and output power) as the injection current increased. This stability can be attributed to the following factors: 1) Refractive index matching, performed by introducing ITO between the epoxy and the GaP window layer enhances light extraction; and 2) The ITO layer is used as the current spreading layer to reduce the thermal accumulation in the epilayers.