X射线干涉光刻方法制备表面增强拉曼散射基底

Fabrication of surface enhanced Raman scattering substrate by X-ray interference lithography

表面增强拉曼散射(Surface-enhanced Raman Scatting,SERS)是一种非常重要的化合物分析技术,在光谱分析、生物传感等领域有着广泛的应用。理想的SERS基底需要同时具有高灵敏度和高均一性,这就需要制备一种大面积并且周期小于100 nm的金属纳米阵列。同步辐射X射线干涉光刻技术具有很高的光刻分辨能力和均匀性,可以制备高密度的金属纳米阵列。利用X射线干涉光刻方法制备了区域面积为320μm×440μm和周期为100 nm的二维周期结构,同时保持了高复制性和优异的均匀性。金属纳米阵列作为表面增强拉曼散射基底时可以提供很好的灵敏度和重复性。对于R6G染料,最低探测极限可达10-9 mol·L-1。在单片样品内的均匀性良好,相对标准偏差为6.72%。此外,表面拉曼增强基底能重复利用,可进一步降低成本。

Background： Surface enhanced Raman scattering （SERS） has become an important molecular detection technology in the field of spectral analysis and biosensing during the last several decades. SERS substrates are usually fabricated by electron beam lithography （EBL）, focus ion beam lithography （FIB）, nanoimprint lithography （NIL）, scanning probe lithography （SPL） and laser interference lithography （LIL）. However, it is still a challenge to fabricate arrays with large area, small period and high output. Purpose： This study aims to rapidly fabricate a SERS substrate with large area and sub 100-nm pitch. Methods： The SERS substrates were prepared by using X-ray interference lithography （XIL）, then scanning electron microscope （SEM）, atomic force microscope （AFM） and Raman spectrum were employed to examine their characteristics. Results： The detective limitation of SERS substrate can be as low to 10-9 mol·L^-1. The relative standard deviations are achieved to be less than 10%. Conclusion： The SERS substrate with the advantages of sensitivity and reproductive provides a promising approach for future SERS applications.