Annealing effect and photoluminescence properties in Tm+-implanted ZnO crystal

ZnO crystals were implanted by Tm+ ions at 500 keV with different doses at room temperature. The lattice damage tends to saturate at dose higher than 3 x 10(15) ions cm(-2), indicating a strong irradiation resistance of ZnO. Post-implant annealing at temperature from 800 to 1050 degrees C is performed to activate Tm ion optically. Annealing higher than 950 degrees C resulted in out-diffusion of Tm ions. Photoluminescence was measured at room temperature with UV and green excitation, luminescence of transition H-3(4) -> H-3(6) from Tm3+ and concentration quenching behavior is observed in samples suffering 800 degrees C annealing for 30 min. Typical emission bands from ZnO crystal are detected in both virgin and the implanted samples. The results show that the implanted Tm+ seems serving as deep traps to contribute to the red band emission. (C) 2011 Elsevier B.V. All rights reserved.