Simple air oxidation synthesis and optical properties of S-doped ZnO microspheres

The S-doped ZnO microspheres with average diameter of 3 micrometers (μm) have been successfully synthesized by a simple air oxidation process of ZnS precursor. X-ray diffractometer (XRD) pattern indicates that the as-obtained sample is composed of ZnO and ZnS. The scanning electron microscopy (SEM) image shows that the exterior surfaces of the microspheres are composed of many nanoparticles with an average grain size of 100 nanometers (nm). The photoluminescence (PL) spectra show the broad excitation region with the main peak at 370 nm and strong green emission centered at 500 nm, which can be attributed to the oxygen vacancies caused by S replacement of O.