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Title: Structures of self-assembled n -alkanethiols on gold by reflection high-energy electron diffraction
The structures of long-chain alkanethiols (C 18 H 37 SH) chemisorbed on an Au(111) single crystal were investigated using reflection high-energy electron diffraction (RHEED). The primary structure observed as a major species in the as-deposited films contains gold adatoms below the sulfur headgroups. Between the small ordered domains with the alkyl chains tilting toward six directions are azimuthally disorderly packed regions, with a similar average tilt of 30.2°. In contrast, a significant reduction in the coverage of gold adatoms is found in the thermally-induced phase. This superlattice is shown to contain a mixture of two sulfur arrangements, both of which exhibit a small S–S distance, and the pairing of the aliphatic chains. A microscopic picture is then given for the structural transition. These findings demonstrate how the RHEED technique may be used to resolve structures of nanometer-thick thin films with multiple orders at the interfaces.  more » « less
Award ID(s):
1653903
PAR ID:
10215217
Author(s) / Creator(s):
;
Date Published:
Journal Name:
Physical Chemistry Chemical Physics
Volume:
22
Issue:
30
ISSN:
1463-9076
Page Range / eLocation ID:
17325 to 17335
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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