Study of SERS activity of different gold nanostructures prepared by electron beam lithography

Abstract

Plasmonic metal nanostructure prepared by photolithography technology can be used as a uniform and stable substrate with high SERS activity. However, there is only limited research on the precisely regulated metal nanostructures and the systematic studies on the relation between the structure and SERS response. Herein, different gold nanostructure arrays (including circles, equilateral triangles, squares, regular pentagons, regular hexagons, pentagrams, and hexagram) have been prepared using electron beam lithography (EBL). Rhodamine B were employed as the probe molecule. The effect of the shapes, sizes (s), spacing (d), and rotation angle (α) of different shapes gold on SERS activities were systematically investigated under the excitation of 532 nm laser. Further finite element method based electromagnetic field simulations unveiled the correlation between the local electromagnetic field strengths and the SERS activities, which also verified the proportional relation between the fourth power of the electromagnetic field intensity (L_E) and enhancement factor (EF).