title: Thickness dependence of the crystallization of Au/glass ultrathin films.
abstract: The crystallization of Au/glass ultrathin films for surface plasmon resonance (SPR) biosensor has been studied using synchrotron X-ray scattering and field emission scanning electron microscope. In films thinner than 30 nm, crystallized Au grains with [111] preferred orientation were formed in the as-deposited amorphous precursor. In film with 58-nm thickness, however, Au (200) powder grains existed on top of the Au (111)-oriented grains near the interface. At the annealing temperature of 400 degrees C, the Au (200) powder grains disappeared, while the Au (111)-oriented grains grew further. The behavior of the surface morphology of Au thin films post-annealed at 400 degrees C was consistent with the thickness dependence of the crystallization. In a 10-nm-thick film, the Au (111)-oriented grains fully crystallized, and then became separated with each other. By increasing to 30-nm film thickness, the Au (111)-oriented grains grew further, coalesced into large columnar-type grains, and showed smooth surface. We suggest that the appropriate thickness of Au/glass thin film for SPR biosensor need over 30-nm-thick, considering smooth surface.
authors.affiliation: Department of Nano Materials Engineering, Kyungpook National University, Sangju, Kyungpook 742-711, Korea.
authors.forename: Tae-Sik
authors.initials: TS
authors.lastname: Cho
authors.forename: Jin-Woo
authors.initials: JW
authors.lastname: Kim
mesh_terms: D003460:Crystallization / Q000379:methods*; D005898:Glass / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008567:Membranes, Artificial; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D008567:Membranes, Artificial; D006046:Gold