Cathodoluminescence Property of ZnO Nanophosphors Prepared by Laser Ablation

Abstract

ZnO nanophosphors with a diameter of 7–50 nm have been fabricated under an oxygen gas atmosphere at room temperature by evaporating ZnO powder or Zn targets using pulsed laser ablation. The size and uniformity of ZnO nanophosphors strongly depend on oxygen gas pressure. Results of cathodoluminescence analysis show strong ultraviolet, blue, green, and green-yellow emissions from ZnO nanophosphors excited by a ∼150 eV low-energy electron beam emitted from carbon nanotubes, depending upon the target material and oxygen gas pressure. Ultraviolet, blue, green, and green-yellow emissions can be attributed to the transitions from the conduction band to the valence band, the Zni level to the VZn level or the valence band, the VO level to the valence band, and the Zni level to the Oi level, respectively.