HIGH EFFICIENCY NITRIDE LEDS FOR USE IN SOLID STATE LIGHTING APPLICATIONS

摘要

High densities of vertical threading dislocations (VTDs) negatively influence internal quantum efficiencies of nitride-based light emitting diodes (LEDs). Recent improvements in the growth of cantilever epitaxy have allowed us to more effectively turn dislocations over the post region resulting in large regions (200 μm~2) of low dislocation density material. Using cantilever epitaxy, we have reduced the dislocation density to 2 - 3 x 10~7 VTDs/cm~2 for regions which span multiple wing and post regions. Near UV InGaN/GaN multiple quantum well LEDs were grown using cantilever epitaxy and compared to identical LEDs grown on planar sapphire. CE-LEDs showed a 3.7 times improvement in output power for room temperature operation at 50 mA (103 A/cm~2).