Examining Ultramicroelectrodes for Scanning Electrochemical Microscopy by White Light Vertical Scanning Interferometry and Filling Recessed Tips by Electrodeposition of Gold
Examining Ultramicroelectrodes for Scanning Electrochemical Microscopy by White Light Vertical Scanning Interferometry and Filling Recessed Tips by Electrodeposition of Gold
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DOI：
10.1021/ac300863r
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发表时间：
2012-06-05
影响因子：
7.4
通讯作者：
Bard, Allen J.
中科院分区：
文献类型：
--
作者：
Chang, Jinho;Leonard, Kevin C.;Bard, Allen J.
本文提出了一种用白光垂直扫描干涉法(VSI)快速、直接检测超微电极(UME)的技术。这项技术在不破坏或修改UME的情况下获得纳米分辨率的地形信息以及在金属凹陷在绝缘护套下方的情况下识别尖端特别有用。对金属半径a=25µm、相对绝缘鞘半径Rg=2和a=5µm、Rg=1.5的两个金UME进行了研究，测得金凹陷的平均深度分别为1.15µm和910 nm。电沉积金被用来填充凹陷的孔洞，深度减少到接近200 nm。用电沉积金电极和常规微电极(a=25µm)分别作为针尖和衬底，获得了600 nm的针尖/衬底距离，使扫描电化学显微镜(SECM)在近距离处于正反馈模式，这对于快速动力学测量是有用的。
In this paper, we present a technique to rapidly and directly examine ultramicroelectrodes (UMEs) by white light vertical scanning interferometry (VSI). This technique is especially useful in obtaining topographic information with nanometer resolution without destruction or modification of the UME and in recognizing tips where the metal is recessed below the insulating sheath. Two gold UMEs, one with a metal radius a = 25 mu m and relative insulating sheath radius RG = 2 and the other with a = 5 mu m and RG = similar to 1.5, were examined, and the average depth of the gold recessions was determined to be 1.15 mu m and 910 nm, respectively. Electrodeposition of gold was performed to fill the recessed hole, and the depth was reduced to similar to 200 nm. With the electrodeposited gold electrode and a conventional microelectrode (a = 25 mu m) as a tip and substrate, respectively, a tip/substrate distance, d, of 600 nm was achieved allowing scanning electrochemical microscopy (SECM) in positive feedback mode at a close distance, which is useful for measuring fast kinetics.