MQWs InGaN/GaN LED with embedded micro-mirror array in the epitaxial-lateral-overgrowth gallium nitride for light extraction enhancement.

Multi-quantum wells (MQWs) InGaN/GaN LEDs, 300 microm x 300 microm chip size, were fabricated with Ta(2)O(5) / SiO(2) dielectric multi-layer micro-mirror array (MMA) embedded in the epitaxiallateral- overgrowth (ELOG) gallium nitride (GaN) on the c-plane sapphire substrate. MQWs InGaN/GaN LEDs with ELOG embedded patterned SiO(2) array (P-SiO(2)) of the same dimension as the MMA were also fabricated for comparison. Dislocation density was reduced for the ELOG samples.

Light extraction enhancement for InGaN/GaN LED by three dimensional auto-cloned photonics crystal.

Three dimensional (3-D) auto-cloned photonics crystal (APhC) of Ta2O5/SiO2 multi-layers was fabricated on the backside of the sapphire wafer that had InGaN/GaN multi-quantum well LED on the front side. 94% light extraction enhancement in comparison to the LED without APhC was obtained. Electrical properties of the LED did not altered by the APhC and its fabrication process.

Heat resistive dielectric multi-layer micro-mirror array in epitaxial lateral overgrowth gallium nitride.

Ta2O5 / SiO2 dielectric multi-layer micro-mirror array (MMA) with 3mm mirror size and 6mm array period was fabricated on c-plane sapphire substrate. The MMA was subjected to 1200 degrees C high temperature annealing and remained intact with high reflectance in contrast to the continuous multi-layer for which the layers have undergone severe damage by 1200 degrees C annealing. Epitaxial lateral overgrowth (ELO) of gallium nitride (GaN) was applied to the MMA that was deposited on both sapphire and sapphire with 2:56 mm GaN template.

Surface profile control of the autocloned photonic crystal by ion-beam-sputter deposition with radio-frequency-bias etching.

Growth of the autocloned Ta(2)O(5)/SiO(2) multilayer photonic crystal with a lateral sawtooth period was simulated. Ion-beam sputter (IBS) was applied to deposit the films and radio-frequency-bias (RF-bias) etching was applied simultaneously with the IBS on the Ta(2)O(5) film. Both simulation and experiment showed that the quality of the autocloning can be controlled by the RF-bias power; there is an intermediate power range within which the drop of peak-to-valley height variation of the sawtooth profile can be reduced significantly such that a high degree of autocloning can be achieved.