Optical Properties of Uniaxially Anisotropic Gold Nanostructures Fabricated by Incline Magnetron Sputtering Process

Abstract

Surface-enhanced Raman scattering (SERS) is very useful for a spectroscopic technique that can enhance Raman scattering intensity up to 10¹⁴ times higher than conventional Raman signal due to the electric field enhancement effect. In this study, we fabricated and evaluated gold nanostructures with SERS activity by using incline magnetron sputtering process. Our fabricated SERS-active substrates enable highly sensitive measurement with wide area over about 20×20 mm². The formation of a gradient in the thickness of the gold film was confirmed, and the SEM images showed that the gold nanoparticles deposited on boehmite template were in an elliptical structure. To evaluate the characteristics of the substrate, the SERS measurements of 4,4´-bipyridine (4bpy) were performed by using the polarized irradiation laser. The polarization property evaluation results show that the polarization reflects the uniaxial anisotropy of the nanostructures.