Gold film surface preparation for self-assembled monolayer studies
Gold film surface preparation for self-assembled monolayer studies
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DOI：
10.1021/la0518804
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发表时间：
2007-01-16
期刊：
影响因子：
3.9
通讯作者：
Rowntree, Paul A.
中科院分区：
文献类型：
--
作者：
Kang, Jing;Rowntree, Paul A.
蒸发金膜经常用作生物分子吸附物、纳米颗粒系统、部分和完整单层膜研究的基材。这些研究通常受益于表面的预沉积清洁，去除实验室污染物中偶然吸附的材料。本研究使用扫描隧道显微镜 (STM) 来探索基于磺基变色溶液和食人鱼酸溶液的自组装单层膜文献报告中使用的两种预处理方案的微观后果。这些测量表明，用食人鱼酸处理金/云母表面会导致表面的广泛且不受控制的蚀刻以及表面形貌的严重破坏；长时间曝光会导致表面微晶沉淀，这些微晶在 STM 成像过程中具有很高的移动性。将金/云母表面暴露于磺基铬酸中会导致表面形成仅一层金深的永久蚀刻坑；长时间暴露会导致表面逐渐蚀刻和氧化，最终导致在平坦的金/云母表面上形成 0.33-0.36 nm 高的岛。食人鱼酸溶液比磺基铬酸溶液更容易导致金膜从云母载体上分层。这些结果表明，磺基变色表面处理是一种直接可靠的方法，可消除 Au(111) 纹理表面的有机残留物，同时将结构和化学表面损伤降至最低。
Evaporated gold films are frequently used as substrates for the study of biomolecular adsorbates, nanoparticle systems, amd partial and full monolayer films. These studies often benefit from a predeposition cleaning of the surface that removes adventitiously adsorbed material from laboratory contaminants. Scanning tunneling microscopy (STM) is used in this study to explore the microscopic consequences of two pretreatment protocols used in literature reports of self-assembled monolayers, based on sulfochromic and piranha acid solutions. These measurements show that treatment of the Au/mica surface with piranha acid can lead to extensive and uncontrolled etching of the surface and severe disruption of the surface topography; extended exposure causes the precipitation of crystallites on the surface that are highly mobile during STM imaging processes. Exposure of Au/mica surfaces to sulfochromic acid leads to the formation of permanent etch pits of the surface that are exclusively one Au layer deep; extended exposure leads to progressive etching and oxidation of the surface, ultimately leading to the formation of 0.33-0.36 nm high islands on the otherwise flat Au/mica surface. The piranha acid solutions are significantly more likely to cause the Au film to delaminate from the mica support than are the sulfochromic acid solutions. These results show that sulfochromic surface preparation is a direct and reliable method for the elimination of organic residues from Au(111)-textured surfaces, while causing a minimum of structural and chemical surface damage.