γ-irradiation preparation and phase control of nanocrystalline CdS

gamma-Irradiation has been successfully used to prepare nanocrystalline CdS of sphalerite and wurtzite structure at room temperature. Sodium thiosulfate, mercaptoethanol and carbon disulfide were used as sulfur sources in aqueous solution or anhydrous ethanol. The formation of sphalerite and wurtzite can be controlled by using different sulfur sources in different solvents. Generally, the sulfur sources and solvents with lower polarity tend to produce the cubic wurtzite phase, while those with strong polarity give the hexagonal sphalerite phase. TEM images show that the products in anhydrous ethanol show superior dispersion, and those in aqueous solution aggregate more extensively. Possible mechanisms of the formation of cadmium sulfide in the different systems are proposed.