ZnSe microspheres were synthesized via a facile hydrothermal method under mild conditions using aqueous zinc nitrate and sodium selenite as raw materials. The effects of hydrothermal temperature, reaction time, concentration of NaOH and amount of hydrazine hydrate on the phase structure, morphology and size of final products were carefully investigated. The phase structures, morphologies and optical properties of the final products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. ZnSe microspheres assembled by average size (about 20 nm) nanocrystals were prepared using 20 mL of 1 mol/L NaOH solution and 10 mL of hydrazine hydrate at 180 °C for 4 h. The results show that the products obtained at low hydrothermal temperature and short reaction time have poor crystallinity and contain impurity phases. The appropriate NaOH concentration and amount of hydrazine hydrate ensure to obtain pure ZnSe with spherical morphology and better luminescence property.
