A fundamental understanding of the metal deposition process on organic self-assembled monolayers (SAMs) is important in designing high quality interfaces between metal and organic materials for organic electronic device applications.  The behavior of thermally evaporated Al deposition on S(CH₂)₁₅CH₃ SAMs on Au {1 1 1} is interesting, since a previous report showed a distinct transition in the deposition process from penetration through the SAM to the underlying substrate to cluster generation at the vacuum interface, based on in-situ XPS, IRS, and ToF-SIMS probes [1].  We have now studied this behavior with in-situ AFM to observe the topographic features and electrical conductance properties with increasing Al coverage.  The AFM results confirm Al penetration in the initial stage, then a transition to a uniform growth of metal nanofilaments and finally surface cluster generation.  We have probed the I-V characteristics of individual filaments which can be as small in diameter as single atoms in the limit. 

[1] A. Hooper, G.L. Fisher, K. Konstadinidis, D. Jung, H. Nyugen, R. Opila, R.W. Collins, N. Winograd, and D.L. Allara, J.Am.Chem.Soc., 121, 8052-8064 (1999).