Template-free approach for hydrothermal fabrication of ZnO microspheres

Wurtzite ZnO microspheres, 5.5–11 μm in diameter and with smooth surfaces, were prepared in absolute ethanol via a simple template-free method in the presence of ethylenediamine. The products were characterized using X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. This simple method to fabricate ZnO microspheres shows high yield (>90%) and good reproducibility. The formation process of ZnO microspheres was discussed. The as-obtained ZnO microspheres are expected to provide some immediate advantages for optical, microelectronic, and biological applications.