Laser post-ionization mass spectrometry combined with Scanning Tunneling Microscopy (STM) has been used to investigate processes of ion-stimulated erosion of self-assembled monolayers (SAM) of phenethyl mercaptan C6H5CH2CH2S (PEM) deposited on gold. Results indicate that only PEM fragments are emitted from the surface. Most of the PEM fragments (predominantly C6H5CH2CH3 with m/z= 106) are emitted with thermal kinetic energies. STM images collected on 8 keV H2+-irradiated surfaces with a system tuned to probe electronic states of sulfur atoms show no additional damage induced by irradiation. This indicates that sulfur atoms are not removed from the surface during hydrogen bombardment. It is proposed that the emission of SAM molecules is initiated by chemical reactions which gently break C-S bonds.
|Number of pages
|Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
|Published - 1999
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics