Highly-ordered self-assembled monolayer of alkanethiol on thermally annealed polycrystalline gold films

- Annealing removes the surface roughness and grain boundaries of gold surface.
- High crystallinity of Au substrate induces a high-ordered SAM formation thereon.
- A good ordering of SAM is achieved with sub-micron gold patterns.

We report a gold substrate manipulation from very-flat to highly-curved surfaces with a thermal treatment as a function of annealing temperature, which greatly affects the quality of SAM with respect to density and ordering. Annealing of gold film greatly removes nanometer-scale protrusions, leading to a very-flat surface with a large grain size as comparable with gold coating on mica. The quality of alkanethiol SAM are evaluated using Fourier transform infrared and time of flight secondary ion mass spectroscopy. Our proposed method delivers good ordering between molecules in the SAMs to promote a high density on extremely small areas for a cost-effective and miniaturized biochip.