旋涂自组装胶体纳米球制备 SERS基底的研究

摘要

研究了以旋涂自组装胶体微球来制作纳米结构模板,并在模板的表面采用离子溅射镀膜的方式沉积Au层,制备了AuFON型表面增强拉曼散射(SERS)基底.理论计算出了不同材料的小球在不同直径下所需要配制的分散液浓度.通过扫描电镜观测其表面形貌,结果表明接近理论计算的浓度所制备的基底具有均匀一致的六角密排布,球体间形成10 nm左右的间隙,证明了理论计算的可靠性,且通过离子溅射镀膜后模板表面形成更丰富的表面结构.拉曼表征结果证明具有均匀间隙的六角密排布结构的SERS基底具有更好的SERS性能.采用时域有限差分法(FDTD)对200 nm和400 nm的球形结构进行仿真,在间距均为10 nm的情况下,200 nm的球型结构具有更高的热点密度、更好的增强效果,与实验中拉曼表征的结果一致.%The Au film over nanosphere(AuFON)surface-enhanced Raman scattering(SERS)substrate was fabricated by ion-beam sputtering deposition on the spin self-assembly nanospheres template.Firstly, the paper theoretically calculated the required concentration of monodisperse nanospheres of different ma-terials and different diameters in the spin self-assembly process.The SERS substrate's surface morpholo-gy was observed by scanning electron microscopy(SEM).SERS substrate fabricated by ion-beam sputte-ring deposition had a uniform hexagonal arrangement with nano-gaps of about 10 nm using a nanosphere concentration close to the theoretical calculation.Raman characterization results show that the SERS sub-strate with uniformly hexagonal arrangement had a better performance.Spherical structures with diameters of 200 nm and 400 nm were simulated by finite-difference time-domain(FDTD) method.FDTD simula-tion results show that when the gap between spheres was 10 nm,the spherical structure with the diameter of 200 nm had a higher electromagnetic field enhancement.The smaller nanospheres had a higher hot spot density and better SERS enhancment performance,which was consistent with the Raman character-ization in the experiment.