Tailoring the luminescence emission of ZnO nanostructures by hydrothermal post-treatment in water

ZnO nanorods and nanowires fabricated from solution methods exhibit poor optical properties. Using hydrothermal post-treatment in pure water, the green emission can be significantly suppressed at 250 °C and completely eliminated at 350 °C. Meanwhile, the near-band-edge UV radiative recombination efficiency is greatly improved and the UV emission intensity is increased up to 50 times. The morphology and structure of the ZnO nanostructures remain intact after the treatment. As evidenced by the electron paramagnetic resonance investigation, this simple treatment can completely remove or passivate the point defects responsible for the green emission of as-grown ZnO.