Highly Reproducible and Sensitive SERS Substrates with Ag Inter-Nanoparticle Gaps of 5 nm Fabricated by Ultrathin Aluminum Mask Technique

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• 作者：Qun Fu ; Zhibing Zhan ; Jinxia Dou ; Xianzheng Zheng ; Rui Xu ; Minghong Wu ; Yong Lei
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：June 24, 2015
• 年：2015
• 卷：7
• 期：24
• 页码：13322-13328
• 全文大小：361K
• ISSN：1944-8252

文摘

Applicable surface enhanced Raman scattering (SERS) active substrates require high enhancement factor (EF), excellent spatial reproducibility, and low-cost fabrication method on a large area. Although several SERS substrates with high EF and relative standard deviation (RSD) of signal less than 5% were reported, reliable fabrication for large area SERS substrates with both high sensitivity and high reproducibility via low-cost routes remains a challenge. Here, we report a facile and cost-effective fabrication process for large-scale SERS substrate with Ag inter-nanoparticle (NP) gaps of 5 nm based on ultrathin alumina mask (UTAM) surface pattern technique. Such closely packed Ag NP arrays with high density of electromagnetic field enhancement (鈥渉ot spots鈥? on large area exhibit high SERS activity and excellent reproducibility, simultaneously. Rhodamine 6G molecules with concentration of 1 脳 10^鈥? M are used to determine the SERS performance, and an EF of 鈭?0⁹ is obtained. It should be noted that we obtain RSDs about 2% from 10 random spots on an area of 1 cm², which implies the highly reproducible signals. Finite-difference time-domain simulations further suggest that the enhanced electric field originates from the narrow gap, which agrees well with the experimental results. The low value of RSD and the high EF of SERS signals indicate that the as-prepared substrate may be promising for highly sensitive and uniform SERS detection.