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A novel technique of low-energy N2 neutral beam (NB) (<10 eV) irradiation was investigated as a means of controlling the surface nitridation of self-assembled monolayers (SAMs). This low-energy process without UV photons was able to nitride the surfaces of terphenyl SAMs. Furthermore, by varying the on/off period for irradiation, a pulse-time modulated NB process could be used to control the atomic ratio of nitrogen in terphenyl molecules. Time-of-flight secondary ion mass spectra revealed that one H in the terphenyl group was substituted by a NH2 group because of irradiation by the N2 beam. The data suggested that the low-energy NB technique caused less damage to modified surfaces than the conventional plasma process did. Therefore, we believe that it is a potential damage-free process for modifying the surfaces of soft organic materials and films. [ABSTRACT FROM AUTHOR]

Damage-free surface nitridation of terphenyl methanethiol self-assembled monolayers (TP1-SAMs) was investigated using a novel low-energy N2 neutral beam (NB) irradiation technique. When a conventional inductively coupled plasma process was used, x-ray photoelectron spectra confirmed that the TP1-SAM was quickly broken because ions or ultraviolet (UV) photons enhance the surface decomposition and molecular desorption. Conversely, with the N2 NB radiation process, which is free of ions and UV photons, there was little difference in the atomic ratios of x-ray photoelectron spectra before and after NB irradiation. These results suggest that low-damage surface modification is possible through the authors’ NB technique. [ABSTRACT FROM AUTHOR]