Structural, Optical, and Electrical Characterization of 643 nm Red InGaN Multiquantum Wells Grown on Strain‐Relaxed InGaN Templates

Red‐emitting (≈643 nm) InGaN multiquantum well active device layers and micro‐LEDs are grown by metal organic chemical vapor deposition (MOCVD) on relaxed InGaN templates, the latter created via thermal decomposition of an InGaN underlayer, and examined via power‐ and temperature‐dependent photoluminescence and electrical measurements. Maximum internal quantum efficiencies are determined to be 7.5% at an excitation power density of 13 W cm −2 , radiative recombination occurs through monomolecular recombination, and the fabricated micro‐LEDs do not show any efficiency degradation with decreasing size. Peak on‐wafer external quantum efficiency (EQE) of a 5 × 5 μm 2 device is 0.44%, demonstrating that thermally decomposed InGaN “strain‐relaxing” underlayers may be useful for long wavelength micro‐LED applications.