Self Assembly of n-Alkanethiolate Monolayers on Silver Nano-Structures: Determination of the Apparent Thickness of the Monolayer by Scanning Tunneling Microscopy
Abstract
The STM is employed to monitor the effect of adsorption of an n-alkanethiolate monolayer, from an aqueous solution of the thiol, on the apparent topography of nanoscopic silver adsorption sites. Silver nano-disk structures were electrochemically deposited on graphite surfaces using the STM. The topography of these adsorption sites was then determined in-situ by STM imaging prior to the exposure of the nano-structure to an aqueous solution of an n- alkane thiol. The apparent thickness of the self-assembled monolayer (SAM), estimated from the difference in the nano-structure height measured before and after adsorption of the monolayer, increased linearly with the alkyl chain length for five n-alkane thiols (i.e., CnH(2n+1)SH) having even numbered chain lengths from n=10 to 18. For SAMs of tetradecane thiol, hexadecane thiol, and octadecane thiol, the average height increments equaled the expected all-trans chain length of these molecules indicating that little penetration of the STM tip into the surface of the monolayer occurs during the STM imaging experiment. STM, N-alkane thiols, Biological, Lithography, Passivation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 12, 1994
- Accession Number
- ADA282322
Entities
People
- Jorma A. Virtanen
- Reginald M. Penner
- Weinjie Li
Organizations
- University of California, Irvine