Modification of alkanethiol self-assembled monolayers on Au by single-ion irradiation

We investigated the effects of single-ion impact on a self-assembled monolayer (SAM) made from octadecanethiol (CH3(CH2)17SH) on Au (1 1 1), expecting that the ion impact processes could change the conductivities of SAMs, and could be used for device fabrication. The ion irradiation effect was characterized using Fourier transformation infrared spectroscopy (FTIR) and contact angle measurements. After 3.1 MeV Au ion irradiation, we found that the surface component changed from CH3 to CH2. The ion-affected regions at nano-scale were observed by Scanning tunnelling microscope (STM), the tunnelling conductance in these regions was larger than those in the non-affected regions