1. Collage of Metrology & Measurement Engineering, China Jiliang University, Hangzhou, Zhejiang 310018, China
2. National Institute of Metrology, Beijing 100029, China
Abstract A high gain Raman tip suitable for tip enhanced Raman system (TERS) based on finite difference time domain (FDTD) simulation and its preparation methods are put forward. The near-field electric field distribution of the concave tungsten tip with gold plating thickness of (5～100)nm and with intermediate transition layer materials of 5nm concluding SiO2, Ta2O5, Ti, Cu is simulated and analyzed at the gold hemispherical sample on the gold substrate. The simulation results show that the tip with a gold plating thickness of 50nm and intermediate interlayer of Ti and Cu have the strongest enhancement effect. On this basis, the designed high-gain tip was successfully prepared by magnetron sputtering and the titanium plating time was set at 7s and 120s for gold plating. The tip was cut by focusing ion beam (FIB) and the profile structure of the tip was observed by a scanning electron microscope (SEM), and the size and shape of the coated tip were verified to meet the design requirements. After 4 batches of 20 needles in each batch, repeated coating experiments were carried out, which proved that the designed needles were stable and could be prepared repeatedly.
ZHU Min-hao,GAO Si-tian,HUANG Lu, et al. Reproducible and Accurate Fabrication of High Gain Raman Gold Plated Tips Based on FDTD Simulation[J]. Acta Metrologica Sinica, 2022, 43(4): 464-469.
［1］ Dou T Y, Li Z D, Zhang J J, et al. Nanoscale Structural Characterization of Individual Viral Particles Using Atomic Force Microscope Infrared (AFM-IR) and Tip-Enhanced Raman Spectroscopy (TERS). ［J］. Analytical chemistry , 2020, 92(16), 11297-11304.
［2］ 张明倩. 透射/反射式针尖增强拉曼光谱术关键技术与实验研究 ［D］. 北京:清华大学, 2013.
［3］ 曹茂丰, 冯慧姝, 包一凡, 等. 针尖增强拉曼光谱的发展及其在表界面中的应用 ［J］. 厦门大学学报(自然科学版), 2020, 59(05): 778-790.
Cao M F, Feng H S, Bao Y F, et al. Development of tip-enhanced Raman spectroscopy and its application in surfaces and interfaces ［J］. Journal of Xiamen University (NATURAL SCIENCE EDITION) , 2020, 59(05): 778-790.
［4］ Hppener C, Schacher F H, Deckert V. Multimodal Characterization of Resin Embedded and Sliced Polymer Nanoparticles by Means of Tip-Enhanced Raman Spectroscopy and Force-Distance Curve Based Atomic Force Microscopy ［J］. Small , 2020, 16(17): 1907418.
［5］ 汪峰, 马小东, 戴长建. 部分碳系材料的拉曼光谱研究 ［J］. Applied Physics , 2013, 3(3): 77-80.
Wang F, Ma X D, Dai C J. Study on Raman Spectra of Some Carbon Materials ［J］. Applied Physics , 2013, 3(3): 77-80.
［6］ 薄涛,胡佳成,蔡晋辉, 等. 内凹形针尖的拉曼散射增强特性［J］. 计量学报, 2020, 41(9): 1033-1038.
Bo T, Hu J C, Cai J H, et al. Raman Scattering Enhancement Characteristic of Concave Tip［J］. Acta Metrologica Sinica , 2020, 41(9): 1033-1038.
［7］ Ren B, Picardi G , Pettinger B. Preparation of gold tips suitable for tip-enhanced Raman spectroscopy and light emission by electrochemical etching ［J］. Review of entific Instruments , 2004, 75(4): 837-841.
［8］ Zhang W, Yeo B S, Schmid T, et al. Single Molecule Tip-Enhanced Raman Spectroscopy with Silver Tips ［J］. The Journal of Physical Chemistry C , 2007, 111(4): 1733-1738.
［9］ 冯仕靓, 王靖宇, 陈舒, 等. 表面等离激元“热点”的可控激发及近场增强光谱学 ［J］. 物理学报, 2019, 68(14): 147801.
Feng S L, Wang J Y, Chen S, et al. Surface plasmon resonance “hot spots” and near-field enhanced spectroscopy at interfaces ［J］. Acta physica Sinica , 2019, 68 (14): 147801.
［10］ 高思田, 施玉书, 李伟, 等. 大长径比台阶钨探针制备方法研究 ［J］. 计量学报, 2017, 38(z1): 47-50.
Gao S T, Shi Y S, Li W, et al. Research on the Fabrication Method of High Length-to-width Ratio Tungsten Tip with a Step ［J］. Acta Metrologica Sinica , 2017, 38(S1): 47-50.
［11］ 陈军. 针尖增强拉曼光谱仪的光学系统设计 ［D］. 厦门: 厦门大学, 2019.
［12］ 都伯林,高思田,黄鹭, 等. 适用于TERS系统的金修饰钨丝探针制备和研究［J］. 计量学报, 2020, 41(12): 1456-1460.
Du B L, Gao S T, Huang L, et al. Study and Preparation of Gold Modified Tungsten Tip for Tip-enhanced Raman Spectroscopy［J］. Acta Metrologica Sinica , 2020, 41(12): 1456-1460.
［13］ 范爱玲, 常随杰, 薛迎坤, 等. 过渡层对钨螺旋线表面无氰镀金质量的影响 ［J］. 稀有金属材料与工程, 2015, 44(3): 612-615.
Fan A L, Chang S J, Xue Y K, et al. Effect of Transition Layer on the Quality of Non-Cyanide Electrodeposited Gold Film on Tungsten Helix ［J］. Rare metal materials and engineering , 2015, 44(3): 612-615.
［14］ Lopa N S, Rahman M M, Ahmed F, et al. Simple, low-cost, sensitive and label-free aptasensor for the detection of cardiac troponin I based on a gold nanoparticles modified titanium foil ［J］. Biosensors and Bioelectronics , 2019, 126(1): 381-388.
［15］ Meng L, Huang T, Wang X, et al. Gold-coated AFM tips for tip-enhanced Raman spectroscopy: theoretical calculation and experimental demonstration ［J］. Optics express , 2015, 23(11): 13804-13813.
［16］ 祝雷, 吴世法, 李亚琴. 镀银膜光探针尖与银粒子间场增强最佳条件的FDTD模拟研究 ［J］. 激光杂志, 2007, 28(6): 84-86.
Zhu L, Wu S F, Li Y Q. The Study of Optimal Parameters of Field Enhancement between the Pyramidal Silver-coated Probe Tip and the Silver Nano-particle by FDTD Method ［J］. Journal of laser , 2007, 28(6): 84-86.
［17］ Bright T J, Watjen J I, Zhang Z M, et al. Infrared optical properties of amorphous and nanocrystalline Ta2O5 thin films ［J］. Journal of Applied Physics , 2013, 114(8): 083515.
［18］ Johnson P B, Christy R W. Optical constants of transition metals: Ti, V, Cr, Mn, Fe, Co, Ni, and Pd ［J］. Physical Review B , 1974, 9(12): 5056.
［19］ 徐靖涛, 高思田, 黄鹭, 等. 基于电化学腐蚀法的钨探针制备装置研究 ［J］. 计量学报, 2018, 39(3): 294-298.
Xu J T, Gao S T, Huang L, et al. Research on Tungsten Probe Fabrication DeviceBased on the Electrochemical Etching Method ［J］. Acta metrologica Sinica , 2018, 39(3): 294-298.
［20］ Liu Y L, Liu F, Wu Q, et al. Effect of bias voltage on microstructure and nanomechanical properties of Ti films ［J］. Transactions of Nonferrous Metals Society of China , 2014, 24(9): 2870-2876.
2022, Vol. 43 
