Co-doped ZnO and as-grown ZnO single crystals were irradiated by 2.5 MeV neutrons from D-D reaction on a neutron generator

and the structural and optical properties were investigated by X-ray diffraction(XRD)

photoluminescence(PL) and optical transmittance at room temperature.The results indicated that a great number of defects of oxygen vacancies(VO) and antisite oxygen(OZn) were introduced in the as-grown ZnO

and a few defects of interstitial zinc(Zni) and interstitial oxygen(Oi) were introduced after irradiation.The nanoclusters of metallic cobalt and cobalt oxides in the Co-doped ZnO disappeared after the neutron irradiation

and a great many Co2+ ions substituted for Zn2+ ions moved away probably from the lattice site due to the fast-neutron collision.The defects of interstitial cobalt impurities and zinc vacancies(VZn) were formed in the Co-doped ZnO irradiated by fast neutrons.The fast-neutron-irradiated samples are still of wurtzite structure and in c-axis orientation.This work shows that ZnO and Co-doped ZnO semiconductors have great radiation hardness

hence their potential of space applications

and the findings are of help in studying point defects of ZnO.