Abstract-Cadmium sulfide quantum dots have been synthesized by wet chemical deposition from an aque ous solution. The sizes of the quantum dots determined by dynamic light scattering directly in the colloidal solution and by intermittent contact atomic force microscopy in the dry sediment agree with each other. It has been found that splitting of the fluorescence peaks of the quantum dots can be affected by the disorder of the atomic structure of cadmium sulfide quantum dots.