表面增强拉曼(SERS)作为一种分析手段, 具有高灵敏度、 高选择性、 高重复性、 非破坏性等优点, 在过去的几十年中, 被广泛应用在成分检测、 环境科学、 生物医药及传感器等领域。 其中以金、 银等贵金属纳米颗粒薄膜在表面增强拉曼(SERS)活性基底方面得到了更为广泛的应用。 SERS技术一个关键的因素是如何制设计并备具有大面积、 高增强能力及高重复性、 可循环使用的SERS基底。 通常, 贵金属纳米颗粒规则阵列结构的单元颗粒电磁增强特性及其颗粒间的电磁耦合增强特性的综合作用可大力提升SERS基底的探测性能。 然而, 利用传统微纳米加工方法如光刻、 电子束光刻等方法制备得到的贵金属纳米阵列结构的表面粗糙度不够理想。 结合光刻与化学置换方法制备金纳米颗粒四方点阵列孔洞结构, 并研究其作为SERS基底的电磁增强特性。 具体研究利用光刻法在硅衬底上制备了规则排列的四方点阵列孔洞结构, 用磁控溅射在其表面镀上金属铁膜; 接着在衬底上旋涂浓度为1.893 8 mol·L-1的氯金酸液膜, 在孔洞内铁和氯金酸发生置换反应, 进而孔洞生成金纳米颗粒, 最终得到金纳米颗粒四方点阵SERS活性基底。 采用罗丹明6G(R6G)分子作为探测分子测试不同金纳米颗粒阵列结构基底的SERS谱。 实验结果表明, 随着化学置换反应时间的延长, 金纳米颗粒排列更加紧凑有序, SERS谱增强性能更好。

Surface enhanced Raman Spectroscopy (SERS), as an analytical method, has the notable advantages of high sensitivity, high selectivity, high reproducibility and non-destructivity. It has been widely used in component characterization, environmental science, biomedicine, biosensors and other fields in the recent decades. Among them, gold and silver and other noble metal nanoparticles-based films have been widely used for SERS active substrates. A key factor in SERS is how to design and fabricate SERS substrates with large size, high enhancement, high repeatability, and recyclability. In general, the combined effect of the electromagnetic enhancement of the noble nanoparticles in a regular array and the enhancement of the electromagnetic coupling among the nanoparticles enhance the detection performance of the SERS substrate. However, the surface roughness of the nanostructures prepared by conventional methods such as photolithography and electron beam lithography is not enough. In this paper, we developed a method for the fabrication of gold nanoparticles tetragonal array pore structure by the combination of photolithography and chemical replacement methods. And, the electromagnetic enhancement properties SERS signal of the fabricated Au nanoparticles array substrates were investigated. The regular round holes array were etched with a tetragonal lattice structure on the silicon by photolithography. Then, the Fe film was deposited on the holes array by magnetron sputtering. After that, the chloroauric acid liquid membrane with a concentration of 1.893 8 mol·L-1 was spin-coated into the holes array on the substrate. The Fe film was then replaced with Au nanoparticles array in the iron holes array. Thus, the fabrication of SERS substrate with gold nanoparticles square lattice was completed. Based on the scanning electron microscopy (SEM) of the microstructure of the substrate, the gold nanoparticles deposited on the substrate were more and larger with the increasing reaction time between the iron film and the chloroauric acid solution. In order to verify the difference in nanostructure caused by different replacement time, the electromagnetic enhancement properties of the prepared gold nanoparticles array was characterized with SERS measurements. The SERS spectra of Au nanostructured substrate were measured by using rhodamine 6G (R6G) as probe molecule. The experimental results showed that the gold nanoparticles were more compact and order with a longer replacement time, and we can get the corresponding stronger SERS signal.