STM Imaging Of Self Assembled Monolayers of 1-Octanethiol (CH3(CH2)7SH) on a Gold Mica Substrate Using The Nanosurf easyScan 2 STM

Topics Covered

Background
SAM Molecule Images
EasyScan 2 STM

Background

STM images on self-assembled monolayers (SAMs) of 1-octanethiol (CH3(CH2)7SH) on a gold/mica substrate. As the sulfur atom binds to the surface it removes gold atoms and single atom deep etch pits are formed (circles seen in Figure 1).

SAM Molecule Images

The SAM molecules stand up on the surface and are tilted at ~30° to the surface normal. Boundaries between domains of molecules with different tilt directions can be seen in Figure 2. Individual molecules are discerned in Figure 3 as well as the characteristic c(4x2) rectangular reconstruction that many thiol-SAMs adopt.

Figure 1.STM image of self-assembled monolayers (SAMs) of 1-octanethiol (CH3(CH2)7SH) on a gold/mica substrate - 150nm x 150nm image

Figure 2.STM image of self-assembled monolayers (SAMs) of 1-octanethiol (CH3(CH2)7SH) on a gold/mica substrate - 32nm x 32nm image

Figure 3.STM image of self-assembled monolayers (SAMs) of 1-octanethiol (CH3(CH2)7SH) on a gold/mica substrate - 6nm x 6nm image

EasyScan 2 STM

These measurements were made using a EasyScan 2 STM with mechanically cut Pt-Ir tips. The gold was flame-annealed prior to adsorption of 1-octanethiol from ethanol solution. Tunneling parameters were 0.02 nA and1 V.

Data courtesy of Erin Iski and Charles Sykes of Tufts University Boston

Source: Nanosurf
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Date Added: Oct 26, 2006 | Updated: Jun 11, 2013
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