Intense green luminescence from Eu2+ -doped ZnO microstructures

We fabricated Eu2+-doped ZnO microstructures by thermal evaporation. Their structures were micrometer-size grains with smooth surfaces or nanometer-size needles. Morphology depended on the temperature region where structures were grown. A strong green luminescence at room temperature is demonstrated. This is attributed to the efficient energy transfer from the ZnO matrix to Eu2+ ions and their 5d-4f transitions.