A study of photoluminescence and micro-Raman scattering in C-implanted GaN

GaN samples (no yellow luminescence) in their as-grown states were implanted with 1013-1017 C ions/cm2 and studied by photoluminescence spectra and micro-Raman scattering spectra. The photoluminescence study showed that yellow luminescence were produced in the C-implanted GaN after 950 degree C annealing, and the peaks of the near band edge emissions showed blue-shifts after C implantation. The Raman measurements indicated that the stresses in GaN films did not change after C implantation. The samples implanted with 1015 cm-2 carbon ions had the Raman peak at 300 cm-1, which is associated to the disorder-activated Raman scattering. However, further increasing the implantation dose resulted decreased intensity of the 300 cm-1 peak, due to the ion beam current increase with the implantation dose. (authors)