Reusable three-dimensional nanostructured substrates for surface-enhanced Raman scattering
1 Department of Physics & Tsinghua-Foxconn Nanotechnology Research Center, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
2 Collaborative Innovation Center of Quantum Matter, Beijing, China
3 Department of Precision Instruments, State Key Laboratory of Precision Measurement Technology and Instruments, Tsinghua University, Beijing, China
Nanoscale Research Letters 2014, 9:25 doi:10.1186/1556-276X-9-25Published: 13 January 2014
To date, fabricating three-dimensional (3D) nanostructured substrate with small nanogap was a laborious challenge by conventional fabrication techniques. In this article, we address a simple, low-cost, large-area, and spatially controllable method to fabricate 3D nanostructures, involving hemisphere, hemiellipsoid, and pyramidal pits based on nanosphere lithography (NSL). These 3D nanostructures were used as surface-enhanced Raman scattering (SERS) substrates of single Rhodamine 6G (R6G) molecule. The average SERS enhancement factor achieved up to 1011. The inevitably negative influence of the adhesion-promoting intermediate layer of Cr or Ti was resolved by using such kind of 3D nanostructures. The nanostructured quartz substrate is a free platform as a SERS substrate and is nondestructive when altering with different metal films and is recyclable, which avoids the laborious and complicated fabricating procedures.