FINE-STRUCTURE OF NEAR-BAND-EDGE PHOTOLUMINESCENCE IN HE-IRRADIATED GAN GROWN ON SIC()

The effect of He ion implantation on the optical properties of epitaxi al GaN-on-SiC was studied. We observed that He+ irradiation increases the relative intensity of the ''blue emission'' and resistivity of GaN films and decreases the intensity of the near-band-edge photoluminesc ence, Because the intensity of the main peak is drastically decreased, the fine structure of the near-band-edge photoluminescence in GaN aft er He+ irradiation was observed. From a comparison of observed sharp l ines with photoluminescence peaks of GaN doped with oxygen, we conclud e that oxygen can produce a complex, which is characterized by a stron g localization of free carriers and a large lattice distortion. The ze ro-phonon line of this defect has energy close to the band-gap energy of GaN, (C) 1998 American Institute of Physics.