Silver sulfide and cadmium sulfide nanoparticles of controllable sizes are synthesized using a water-in-hexane microemulsion method and stabilized by dodecanethiol. The stabilized metal sulfide nanoparticles can be deposited homogenously on flat substrates forming ordered 2-D arrays in supercritical fluid carbon dioxide (Sc-CO2). The use of Sc-CO2 leaves the particles unaffected by dewetting effects Caused by traditional solvents and produces uniform arrays. The Sc-CO2 deposition technique is capable of filling nanoparticles in nanostructures of silicon wafers which is difficult to accomplish by conventional solvent evaporation methods.