Acceptor-like deep level defects in ion-implanted ZnO

N-type ZnO samples have been implanted with MeV Zn + ions at room temperature to doses between 1 × 10 8 and 2 × 10 10 cm - 2 , and the defect evolution has been studied by capacitance-voltage and deep level transient spectroscopy measurements. The results show a dose dependent compensation by acceptor-like defects along the implantation depth profile, and at least four ion-induced deep-level defects arise, where two levels with energy positions of 1.06 and 1.2eV below the conduction band increase linearly with ion dose and are attributed to intrinsic defects. Moreover, a re-distribution of defects as a function of depth is observed already at temperatures below 400K.