Scanning Tunneling Microscopy and Spectroscopy Studies of4-Methyl- 4'-(n-mercaptoalkyl)biphenyls on AuA ) 1)

4-Methyl-4’-(n-mercaptoalkyl)biphenyl (CH3� C6H4� C6H4� A2)n� SH, n = 3–6, BPn) monolayers assembled on AuA @ 1) in 1,3,5,-trimethylbenzene (TMB) at varioustemperaturesare s by scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). High resolution STM images reveal that BP3 and BP5 form a ( ffiffiffi p @2 ffiffiffi p ) repeating motif superimposed on a temperature-dependent Moire pattern. BP4 and BP6 adlayersare characterized by a coexisting (2 ffiffiffi p @5 ffiffiffi p ) majority phase and a temperature-dependent (3 @ p ffiffiffi p ) minority phase. Assembly at 608 Co r 908C leadsto p = 5. Compression of the adlayer was found at higher temperatures. Combined with high-resolution structure experiments, the electronic characteristics of BP3 and BP4 self-assembled monolayers (SAMs) were studied by monitoring current–distance (iT–Dz) and current–voltage (iT–Ebias) characteristics in TMB employing a gold STM tip j BPn j AuA @ 1) configuration. The semilogarithmic (iT–Dz) plotsyielded three �� ��