Large-area high-performance SERS substrates with deep controllable sub-10-nm gap structure fabricated by depositing Au film on the cicada wing
The MOE Key Laboratory of Weak-Light Nonlinear Photonics, Tianjin Key Laboratory of Photonics and Technology, TEDA Applied Physics School and School of Physics, Nankai University, Tianjin 300457, China
Nanoscale Research Letters 2013, 8:437 doi:10.1186/1556-276X-8-437Published: 22 October 2013
Noble metal nanogap structure supports strong surface-enhanced Raman scattering (SERS) which can be used to detect single molecules. However, the lack of reproducible fabrication techniques with nanometer-level control over the gap size has limited practical applications. In this letter, by depositing the Au film onto the cicada wing, we engineer the ordered array of nanopillar structures on the wing to form large-area high-performance SERS substrates. Through the control of the thickness of the Au film deposited onto the cicada wing, the gap sizes between neighboring nanopillars are fine defined. SERS substrates with sub-10-nm gap sizes are obtained, which have the highest average Raman enhancement factor (EF) larger than 2 × 108, about 40 times as large as that of commercial Klarite® substrates. The cicada wings used as templates are natural and environment-friendly. The depositing method is low cost and high throughput so that our large-area high-performance SERS substrates have great advantage for chemical/biological sensing applications.