Effect of coalescence layer thickness on the properties of thin‐chip InGaN/GaN light emitting diodes with embedded photonic quasi‐crystal structures

The simulation, fabrication and optical characterization of InGaN/GaN MQW‐LEDs grown by MOVPE over embedded photonic quasi‐crystals (PQCs) are reported. Fully coalesced GaN layers as thin as 140 nm were grown over 1200 nm high air‐gap PQCs using an intermittent pulsed/normal growth method. Simulations and angle‐resolved photoluminescence measurements reveal there are strong interactions between the embedded PQC and a wide range of trapped modes as well as the dominant low order mode. The interaction with a dominant low order mode is most pronounced when the LED cavity above the embedded PQC has fewer guided modes. magnified image 1200 nm high embedded air‐gap PQC overgrown with a 280 nm thick coalesced GaN epitaxial layer by MOVPE.