Effects of Si ion implantation and post-annealing on yellow luminescence from GaN

Abstract

We have studied the effects of Si ion implantation and post-annealing on yellow luminescence (YL) from GaN. Two types of GaN samples grown by the metal-organic chemical vapor deposition method and labeled as GaN1 and GaN2 were studied. The PL spectrum of the as-grown GaN1 sample was dominated by a strong YL and that of the as-grown GaN2 sample was almost free from YL. After Si ion implantation with doses of both 1.3×10 13 and 1.0×10 16 cm −2, the intensity ratios of YL to near band edge (NBE) emission ( I Y/ I NBE) for the GaN1 samples decreased markedly compared with those of the corresponding unimplanted ones both before and after post-annealing at temperatures up to 950°C. However, for the Si-ion-implanted GaN2 sample with a dose of 1.3×10 13 cm −2, I Y/ I NBE increased compared with that of the as-grown one both before and after post-annealing. Besides, the I Y/ I NBE for Si-ion-implanted GaN1 with a dose of 1.3×10 13 cm −2 increased monotonically with annealing temperature. Our results show that only the Si ion implantation being accompanied with high-temperature post-annealing could produce YL. The possible reasons for the marked reduction in I Y/ I NBE for the GaN1 sample after Si-ion-implantation have been discussed.