@article{oai:nagasaki-u.repo.nii.ac.jp:00007433,
 author = {Tomiyama, Noriyuki and Takenaka, Minoru and Kuramoto, Eiichi},
 journal = {長崎大学教育学部自然科学研究報告, Science bulletin of the Faculty of Education, Nagasaki University},
 month = {Feb},
 note = {Positron annihilation studies have been carried out to clarify the radiation induced defects in ZnO single crystals. Vapor-grown ZnO crystals were irradiated at 77 K with 28 MeV electrons. Before irradiation as-grown specimens showed the mean positron lifetime in the range of 160-195 ps. Electron irradiation increased the mean positron lifetime up to 205-210 ps.This long-lifetime disappeared until 473 K during successive isochronal annealing steps. The radiation-induced coloration was anneale out around 523 K. During this stage, the radiation induced oxygen vacancies are thought to be moved away and disapeared. The second recovery stage at around 823 K is thought to be caused by the recovery of small ZnO interstitial clusters fomed through clustering of interstital atoms., 長崎大学教育学部自然科学研究報告. vol.46, p.1-7; 1992},
 pages = {1--7},
 title = {Positron Annihilation Study of Radiation Defects in Zinc Oxide},
 volume = {46},
 year = {1992}
}