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Nitride-Based LEDs With Phosphoric Acid Etched Undercut Sidewalls. P.K Lin. 1. Outline. Introduction Experiments Results and Discussion Conclusion References. 2. Introduction.
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Nitride-Based LEDs With Phosphoric Acid EtchedUndercut Sidewalls P.K Lin 1
Outline • Introduction • Experiments • Results and Discussion • Conclusion • References 2
Introduction • The external quantum efficiency of conventional GaN-based LEDs is limited to only a few percent. In order to increase the light extraction efficiency, We propose a simple defect-selective wet etching method to form oblique sidewalls for GaN-based epitaxial layers with phosphoric acid.it is very important that photons gen-erated in the LEDs can experience multiple opportunitie to find the escape cone. 3
Experiment In0.23GaN0.77-GaN(0.5nm/0.5nm) 250nm In0.23GaN0.77-GaN(3nm/7nm) Air(n=1) GaN(n=2.5) Snell’s low: Sin-1(1/2.5)=23▫ 300nm LED chip size: 250 μmx580 μm 23▫ 4