III-Nitride Based High-Power 340 nm Lasers

Existing ultraviolet laser diodes with wavelengths much shorter than 365 nm suffer from poor performance. This is partially due to limited research in this area, but a large part is also due to material and processing issues unique to deep UV lasers. New approaches to achieving 340 nm III-Nitride lasers are needed to meet the Navy's ambitious goals; traditional approaches to III-Nitrides are unlikely to be able to achieve the desired laser performance. Instead it is necessary to develop revolutionarily novel approaches to the growth and fabrication of AlInGaN based UV lasers. Phase I of this effort involved studying the growth, processing, testing, and demonstration of high power UV LEDs, and the initial demonstration of laser fabrication. This work has laid the ground work for a Phase II effort in which we will pursue novel approached to realizing UV lasers. One of the cornerstones of our novel approach is to use lateral epitaxial overgrowth (LEO) to reduce dislocation density and cracking formation, so as to improve the quality of the active layers. The objective of Phase II will be to demonstrate high average power UV lasers based on these novel designs.