Open AccessHigh efficiency white LEDs with single-crystal ZnO current spreading layers deposited by aqueous solution epitaxy
Author(s) -
Arthur H. Reading,
Jacob J. Richardson,
Chih-Chien Pan,
Shuji Nakamura,
Steven P. DenBaars
Publication year - 2011
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.20.000a13
Subject(s) - materials science , light emitting diode , optoelectronics , indium tin oxide , epitaxy , indium , diode , optics , layer (electronics) , absorption (acoustics) , nanotechnology , physics , composite material
Heteroepitaxial ZnO transparent current spreading layers with low sheet resistances were deposited on GaN-based light emitting diodes using aqueous solution phase epitaxy at temperatures below 90°C. The performance of the LEDs was analyzed and compared to identical devices using electron-beam evaporated indium tin oxide transparent current spreading layers. White LEDs with ZnO layers provided high luminous efficacy–157 lm/W at 0.5A/cm2, and 84.8 lm/W at 35A/cm2, 24% and 50% higher, respectively, than devices with ITO layers. The improvement appears to be due to the enhanced current spreading and low optical absorption provided by the ZnO.