UV/Blue III-Nitride Micro-Cavity Photonic Devices.

摘要

During Phase I duration, we have further improved blue micro-size light emitter output power efficiencies by optimizing the material qualities as well as device structures. During Phase I optional phase duration, we learned how to achieve white light emission from InGaN/GaN QW micro-size emitters. We have employed three-color emitting (red-blue-green) phosphorus coating on near UV micro-size LEDs and conventional LEDs to obtain white light emission. Comparing with coating an yellow-emitting phosphor on blue LEDs, the three-color phosphors approach yielded improved white light color rendering. We have also further developed interconnected microdisk LED technology to enhance the extraction efficiency and improve the current spreading. Large-area LED chips have been successfully fabricated. An output power as high as 50 mW has been achieved in interconnected microdisk blue LEDs with a 3 x 3 mm squared chip area size. Further works dealing with heat management and efficiency improvement are still needed. The technologies developed in the optional phase laid the groundwork for the development of solid-state white lighting, which is a technology with an enormous market interest worldwide for energy savings as well as for pollution reduction. The color down conversion technology developed in the optional phase can be equally applied to the development of full color microdisplays based on III-nitrides.