Thiol flat gold substrate

The fabrication of STM-based molecular junctions have relied - in most reported cases -on the deposition of thiol end-capped molecules as self-assembled monolayers on a flat gold substrate. By using an exceedingly small tip, the measurement of no more than a single or a few molecules becomes possible. A schematic illustration of an STM-based molecular junction is shown in Fig. 10.2. 

Most studies of the adlayer stmcture were performed on thiol monolayers deposited on either gold crystals or annealed Au/mica substrates known to possess large atomically flat terraces. However, recent AFM study of thiols adsorbed on the surface of sputtered gold, which has a granular stmcture, showed the same lattices as those observed for Au(lll) terraces. This implies that even on sputtered gold, monolayers are formed with a high degree of local order . 

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