Radiation damage and near edge optical properties of nitrogen implanted gallium arsenide

Measurements of optical transmission and Rutherford backscattering experiments (RBS) are carried out to investigate the correlation between different defect structures and the near edge optical properties of nitrogen implanted GaAs. The defect structures detected with these methods can be classified into two groups. A point defect-like structure connected with an exponential long tail to the absorption edge and a weak contribution to the dechanneling without any damage peak in the RBS spectra preferably occurs for low dose implantation at Ti = 80 K and for room temperature implantation. A transition to heavily damaged regions connected with a short tail to the absorption edge is formed for higher fluences at Ti = 80 K. In this case damage peaks occur in the RBS spectra and the refractive index change reaches a value of about 10% after formation of a continuous amorphous layer.