In this study, we demonstrated that yellow luminescence (YL) defects can be mitigated with proper annealing or CF4 plasma treatment. Multiple material analyses, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and surface roughness measurements were performed to investigate improvements in GaN film material properties caused by annealing and CF4 plasma treatment. Filling vacancies during the annealing process and incorporating fluorine atoms to bond with dangling bonds during the plasma treatment process may lessen YL defects and decrease YL luminescence. ; SCI