Defects Studies of As-Grown Single Crystal ZnO by Positron

Positron lifetime spectroscopy(PAS) and coincident Doppler broadening(CDB) measurements have been performed in as-grown and annealing single crystal ZnO.The temperature dependence observed in annealed ZnO indicates that the defect is removed after annealing.By combining the Doppler broadening measurements,we inferred that there isn't hydrogen filling the zinc vacancy site in the as-grown ZnO due to the same characteristics in CDB spectra for as-grown and annealed ZnO samples.