Outgoing multiphonon resonant Raman scattering in Be- and C-implanted GaN

We have performed outgoing resonant Raman scattering and photoluminescence measurements on as-grown, Be- and C-implanted GaN in the temperature range of 77-330 K. In implanted GaN after postimplantation annealing at 1100 degr eesC, LO multiphonons up to the seventh order were observed with the very s trong 4LO and 5LO modes at similar to 2955 and similar to 3690 cm(-1), resp ectively, showing extraordinary resonance behavior. With increasing sample temperature, these two modes significantly decreased and increased in inten sity, respectively. The phenomenon is attributed to the variation of resona nt conditions due to the shift of the bandgap energy. Meanwhile, the combin ation of E-2(high) and quasi-LO phonons was strongly enhanced by quasi-LO p honon involving and thus the corresponding overtones can be clearly observe d even up to the sixth order (m = 6).