Zubiaga, ATuomisto, FColeman, Victoria AJagadish, Chennupati2015-12-082015-12-080169-4332http://hdl.handle.net/1885/35305Slow positrons have been used to study ZnO layers grown on a-axis sapphire and irradiated by 2 MeV O+ ions to fluences from 1012 cm-2 to 1017 cm-2. At low fluences Zn vacancies are observed, and their introduction rate is estimated as 2000 cm-1. At the highest fluences of 1016-1017 cm-2 vacancy clusters are formed. The extent of the primary damage and its recovery is discussed.Keywords: Corundum; Semiconducting zinc compounds; Zinc alloys; Zinc oxide; Clusterization; Irradiation; Point-Defects; Positron Spectroscopy; Slow positrons; Thin-Films; Vacancy Defects; ZnO; ZnO layers; Vacancies Irradiation; Point-Defects; Positron Spectroscopy; Thin-Films; ZnO200810.1016/j.apsusc.2008.05.1972015-12-08