摘要
Light-emitting diodes are becoming the alternative for future general lighting applications,with huge energy savings compared to conventional light sources owing to their high efficiency and reliability.Polarized light sources would largely enhance the efficiency in a number of applications,such as in liquid-crystal displays,and also greatly improve contrast in general illumination due to the reduction in indirect glare.Here,we demonstrate light-emitting diodes presenting high-brightness polarized light emission by combining the polarization-preserving and directional extraction properties of embedded photonic-crystals applied to non-polar gallium nitride.A directional enhancement of up to 1.8-fold was observed in the total polarized light emission together with a high polarization degree of 88.7%at 465 nm.We discuss the mechanisms of polarized light emission in non-polar gallium nitride and the photonic-crystal design rules to further increase the light-emitting diode brightness.This work could open the way to polarized white-light emitters through their association with polarization-preserving down-converting phosphors.
基金
The experimental part of this work was performed at University of California,Santa Barbara.This study is based upon work partially supported as part of the‘Center for Energy Efficient Materials’at University of California,Santa Barbara,an Energy Frontier Research Center funded by the US Department of Energy,Office of Science,Office of Basic Energy Sciences under Award Number DE-SC0001009 and by the Solid State Lighting and Energy Center(SSLEC)at the University of California,Santa Barbara.
