This paper describes the selective deposition of mercury (Hg) onto self-assembled dithiols via a chemical vapor deposition (CVD) process. Characterizations of the deposited Hg by atomic force microscopy (AFM) after its chemisorption with the -thiol head groups showed particle-like behavior. The AFM results obtained posed an interesting question regarding the physical state of the deposited Hg: are nanodroplets or nanoparticles formed? The determination of the nano sized-droplets formation of Hg on alkanedithiolate self-assembled monolayers (SAMs) is demonstrated using quartz crystal microbalance (QCM) technique.