Aging effects on the optical properties of an individual Zn-rich ZnO nanowire

Zn-rich ZnO nanowires are fabricated by a facile thermal evaporation method. The aging and post-annealing effects on an individual nanowire are investigated by cathodoluminescence (CL) spectra. For the nanowire aged in air, the intensity of deep-level (DL) emission is gradually strong with aging time, while are almost unchanged if aged in Ar atmosphere. Whether the individual nanowire was post-annealed in air or Ar atmosphere, the intensity of DL emission was gradually enhanced with temperature. Moreover, blue-shift of the DL emission is detected in the nanowire annealed in air. Nevertheless, for the nanowire annealed in Ar, the DL emission is first blue-shift at temperature of 400 °C, then red-shift at 500 and 600 °C. It is found that different defects can induce different DL emission, and the type of defects varies in the products depending on the experimental conditions.

Research highlights▶ The aging and post-annealing effects on an individual Zn-rich ZnO nanowire are investigated by cathodoluminescence (CL) spectra. ▶ For the nanowire aged in air, the intensity of deep-level (DL) emission is gradually strong with aging time, while are almost unchanged if aged in Ar atmosphere. ▶ Blue shift of the DL emission is detected in the nanowire annealed in air. ▶ For the nanowire annealed in Ar, the DL emission is first blue-shift at temperature of 400 °C, then red-shift at 500 and 600 °C.