Experimental Investigation of the Nucleation of Silver on Molybdenite

An experimental investigation has been made of the nucleation of Ag on single-crystal MoS2 for deposition rates in the range 8×1011−7×1013 atoms/cm2·sec and at two substrate temperatures, 30 and 200°C. At the lower deposition rates employed, the Ag deposits were found to be very highly oriented with Ag (111) parallel to MoS2 (0001) and Ag [11̄0] parallel to MoS2 [21̄1̄0]. The smallest Ag clusters detected by transmission electron microscopy were approximately 20 Å in diameter. Nucleation rates were determined for various deposition rates and it was found that the nucleation rate varied linearly with the deposition rate at each temperature. Attempts were made to fit both the capillarity and atomistic theories of thin-film nucleation to the experimental results, and it was found that neither theory could be fitted in a completely consistent manner. Explanations for the differences between theory and experiment are discussed.