SAMs of 11-MUA grown on polycrystalline Au-foils by physical vapor deposition in UHV

Abstract

In the present study, our aim was to prepare and characterize 11-mercaptoundecanoic acid (11-MUA) films on polycrystalline Au-foils grown by physical vapor deposition (PVD) in ultra high vacuum (UHV). When preparing the SAMs by PVD in a UHV chamber, one profits from well defined conditions and exclusion of the influence of air. The Au-samples were cleaned in UHV by Ar-sputtering. In order to characterize the 11-MUA films, mainly thermal desorption spectroscopy (TDS) was applied. TDS measurements revealed monolayer and multilayer desorption. A variety of different masses was observed when desorbing the 11-MUA from the Au-surface. This showed on the one hand the cracking pattern of this molecule in the quadrupole mass spectrometer (QMS) and on the other hand that reactions took place during the adsorption/desorption process. Of particular interest was the question as to the Au-S and the C-S bond breaking.