Self Assembled Alkanethiolate Monolayers as Thin Insulating Films

Abstract

Simple devices that contain alkanethiolate monolayers sandwiched between conducting films were prepared by fixing a gold film to the surface of an alkanethiolate monolayer (on a gold substrate) with silver paint. These devices, and similar devices that did not contain alkanethiolate monolayers, were tested as resistors in d.c . circuits. The devices that contained octadecanethiolate monolayers had resistances of approximately 10¹² Ω, 10 orders of magnitude higher than the resistance of devices that contained no monolayers. Sulfur- terminated alkanethiolate monolayers were prepared by treatment of carboxylic acid-terminated monolayers with vapours of thionyl chloride followed by vapours of hexane-1,6-dithiol. Attempts to use the sulfur-containing groups at the surface of this monolayer as 'molecular glue' to attach a flexible gold film to the surface of the monolayer were unsuccessful.