<p>This study optimized indium gallium nitride (InGaN) quantum wells (QWs) to enhance the emission characteristics of gallium nitride (GaN) blue light-emitting diodes (LEDs) for their application in white light illumination, full-color displays, laser diodes, optical storage probes (blue-ray DVDs), and optical detectors. Phase separation caused by quantum wells of different thicknesses not only leads to the formation of different indium-rich structures, but also to the formation of different dislocation structures with different strain energy levels. Moreover, this phenomenon influences the light emission characteristics of LEDs. In this study, the thickness of InGaN QWs in GaN/InGaN LEDs was first adjusted, followed by analyzing the changes in the indium-rich phase structure of these LEDs through thermal annealing treatment as a post processing technique. Moreover, the light emission characteristics and material structure of the fabricated GaN/InGaN LEDs were examined. High-resolution transmission electron microscopy was used to observe the microstructures and defect structures of InGaN QWs, and scanning electron microscopy was employed to analyze the surface morphology changes of GaN/InGaN thin films. The luminous intensity of LEDs was measured by integrating sphere to analyze the luminous characteristics of the fabricated LEDs; the emission characteristics of quantum wells in these LEDs were analyzed by photoluminescence spectroscopy. By optimizing InGaN QWs, this study enhanced the light emission characteristics of GaN/InGaN LEDs.</p>