Thermo-kinetics study of laser-induced desorption of self-assembled monolayers from gold: case of laser micropatterning.

Laser-induced desorption of self-assembled monolayers (SAMs) from gold surfaces within context of the direct laser patterning methodology was investigated through combining results of a heat diffusion thermal model with desorption kinetics of alkanethiol SAMs. It was found that contrast plots of experimental scanning electron microscopy (SEM) images, which are correlated to surface coverage of SAMs desorbed after laser irradiation, agreed with the theoretically predicted surface composition of SAMs. The surface composition of SAM was then interpreted in terms of the wetting property of the resulting surface. The effect of incident laser beam power and size on the final spatial coverage of SAMs on the surface and feature sizes was investigated both experimentally and by modeling. Theoretical modeling and experimental evidence showed that the resulting feature sizes are wider when the surface is heated by a laser of higher power. Increasing the laser beam size results in broadening of feature sizes. Considering the correlation of the theoretical and experimental results, we concluded that the feature sizes are controllable in a predictable way (using the presented thermal-kinetics model) through varying laser beam power and beam size.