Room temperature ultraviolet emission from ZnO nanocrystallites fabricated by the low temperature oxidation of metallic Zn precursors

We have successfully fabricated ZnO nanocrystallites emitting strong ultraviolet radiation at room temperature via the simple thermal oxidation of metallic Zn precursors at 380 °C. X-ray diffraction measurements showed only the diffraction peak from ZnO, revealing that metallic Zn precursors were successfully oxidized even at the low temperature of 380 °C. The mean size of the ZnO nanocrystallites determined using Scherrerʹs formula was ca. 30 nm. Room temperature photoluminescence measurements using a cw He–Cd laser (λ=325 nm) showed a strong emission peak at 3.27 eV, which was ascribed to free excition recombination. These results suggest that sufficient oxygen can diffuse into the metallic Zn precursors, even at temperatures as low as 380 °C, to allow the fabrication of pure ZnO nanocrystallites.