The yellow luminescence origin of N-polar GaN film grown by metal organic chemical vapor deposition

N-polar GaN films were grown on c-plane sapphire substrates by metal organic chemical vapor deposition and implanted with C or O ions were studied. High-resolution X-ray diffraction results show that, after implantation, there were clear increases in the full widths at half maximum of rocking curves. However, the increases disappeared after annealing at 1050℃ for 30 min. Photoluminescence (PL) spectra obtained from the N-polar GaN films before and after implantation indicated a significant increase in the yellow luminescence (YL) band after C-implantation while O-implantation sample showed only a slight increase. It can be concluded that gallium vacancies and related complex defects were not the major source for YL. The present result confirmed that the implanted C impurity and its complexes are responsible for the increased YL intensities.