Fabrication of large area nanoprism arrays and their application for surface enhanced Raman spectroscopy

Abstract

This work demonstrates the fabrication of metallic nanoprism (triangular nanostructure) arrays using a low-cost and high-throughput process. In the method, the triangular structure is defined by the shadow of a pyramid during angle evaporation of a metal etching mask. The pyramids were created by nanoimprint lithography in polymethylmethacrylate (PMMA) using a mould having an inverse-pyramid-shaped hole array formed by KOH wet etching of silicon. Silver and gold nanoprism arrays with a period of 200 nm and an edge length of 100 nm have been fabricated and used as effective substrates for surface enhanced Raman spectroscopy (SERS) detection of rhodamine 6G (R6G) molecules. Numerical calculations confirmed the great enhancement of electric field near the sharp nanoprism corners, as well as the detrimental effect of the chromium adhesion layer on localized surface plasmon resonance. The current method can also be used to fabricate non-equilateral nanoprism and three-dimensional (3D) nanopyramid arrays, and it can be readily extended to other metals.

Selective synthesis of hexagonal Ag nanoplates in a solution-phase chemical reduction process

“…An Ag superlens can be fabricated when an Ag nanoplate of appropriate thickness is selected and the permittivity of the Ag and the adjacent object are equal and of opposite sign [8]. The resonant plasmons also result in a strong local surface-enhanced electromagnetic field [9], which can increase the scattering intensity of molecules adsorbed on Ag nanoplates and makes the Ag nanoplates good substrates for the detection of small amounts of material, or even single molecules, by surface enhanced Raman spectroscopy (SERS) [10,11]. In addition, Ag nanoplates in solution can be also used as optical limiters, in which the nonlinear scattering of the Ag nanoplates has been proposed to play an important role in the optical limiting effects [12].…”

Near-Field Hot Spots in Gold Nanoplasmonic Templates and Their Use for Surface Enhanced Raman Scattering Sensing Application

“…Near-field localization and studies of SERS on a variety of plasmonic structures have been reported previously by various researchers [11][12][13][14][15]. It is also reported that twodimensional (2D) structures are superior compared to onedimensional (1D) structure.…”

Nanolithography: Status and challenges

“…One of the major influences of NIL technology is the capability of large area printing. Large area patterning with high density and high fidelity have been reported in the earlier reports [46][47]. It has been reported that throughput per imprint station improved fivefold to 10 wafers per hour [43].…”