We synthesized cadmium sulfide (CdS) submicron particles in reverse micelles. We chose the surfactants and the water-to-surfactant molar ratio to influence the formation of reverse micelles such that their average size was 100 nm. The actual size of the particles that we synthesized was consistent with the expected reverse micelle size. The synthesized CdS particles exhibited a strong photoluminescence that comprised an interband emission with a quantum confinement effect and a broad emission that originated from the surface trap states. When combined with the blueshifted absorption edge seen in the submicron particle solution, our prepared submicron particles were an aggregation of semiconductor quantum dots. The submicron-size semiconductor particle is appropriate as an optical trapping target in a variety environments and is beneficial for sophisticated resonant optical manipulation, including enhanced optical trapping force and recoil force manipulation.