基于电化学法的银针尖可控制备

Controllable preparation of silver tips based on electrochemical etching

银针尖在扫描探针显微术和针尖增强拉曼光谱等前沿领域中受到了广泛的关注,但目前使用环状阴极电化学腐蚀出的银针尖尖端"宝塔"状结构较为普遍。本文以制备具有规则几何形状的银针尖为目标,分析了银针尖电化学腐蚀的原理,并结合场效应管快速关断电路和皮安计搭建了银针尖的电化学制备装置。考虑到电化学腐蚀中阴极电极的形状对电解液中电场分布的影响,在实验中着重于不同阴极电极形状对银针尖几何形状的制备实验结果进行了研究。并对不同的电化学制备条件,例如,改变不同的电解液浓度以及不同参考电压所获得的实验结果进行了对比。最后总结出一种采用锥筒形阴极电极来制备具有规则几何形状的银针尖的简便可行方法。

Silver tips have attracted a great deal of attention in frontier fields such as scanning probe microscopy and tip-enhanced Raman spectroscopy. However,the ＂pagoda＂structure of silver tip is common,which is etched with ring cathode in electrochemical preparation. This paper aims to prepare silver tips with regular geometric shapes. The principle of electrochemical etching of silver tips is analyzed. Combined with the fast cut-off circuit and the picoammeter,a silver tip electrochemical preparation device has been set up. Considering the influence of the shape of cathode electrode on the electric field in the electrolyte during electrochemical etching,the experiments on the preparation of silver tips with different cathode electrode shapes are studied. Besides,under other different electrochemical preparation conditions,such as different electrolyte concentrations and reference voltages,silver tip profiles obtained in experiments are compared. Finally,a simple and feasible method to prepare regular geometric shape silver tips using cone cathode is summarized.