DC- and RF-GD-OES measurements of adsorbed organic monolayers on copper
DC- and RF-GD-OES measurements of adsorbed organic monolayers on copper
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DOI：
10.1007/s00216-009-2966-7
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发表时间：
2009-08
影响因子：
4.3
通讯作者：
D. Klemm;V. Hoffmann;K. Wetzig;J. Eckert
中科院分区：
文献类型：
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作者：
D. Klemm;V. Hoffmann;K. Wetzig;J. Eckert
我们的直流（DC）和射频辉光放电光学发射光谱（RF-GD-OES）测量吸附有机单层的灵感来自Shimizu等人的工作，他们在2004年提出了用RF-GD-OES对吸附单层进行深度剖面分析的第一个例子。RF-GD-OES分析亚纳米厚度层的巨大潜力令人惊讶。Shimizu等人不仅讨论了有机单层原子（C， H， N， S）的定性检测，而且还讨论了由于显著的峰序列而导致的分子相对于表面的不同取向的测定。后一种假设在分析界受到质疑。我们打算通过使用先进的真空仪器和硅预溅射来证明GD-OES技术在可靠性和可重复性方面的表面分析潜力。结果表明，可比较的测量结果不仅可以用RF-GD-OES重现，最重要的是，也可以用DC-GD-OES重现。详细描述了在铜衬底上吸附硫脲分子的实验步骤。对其他有机分子，如苯并三唑（BTA）或苯并噻唑（BTH）的进一步实验，反驳了分子相对于表面的取向与峰分离发生之间的预测相关性。最终，在吸附硫脲的情况下实现了有机单层化合物的定量。图c - gd - oes吸附单层硫脲表面深度分布图
Our direct current (DC)- and radiofrequency glow discharge optical emission spectroscopy (RF-GD-OES) measurements of adsorbed organic monolayers were inspired by the work of Shimizu et al., who presented the first example of depth profile analysis of an adsorbed monolayer by RF-GD-OES in 2004. The great potential of RF-GD-OES for analyses of layers with thicknesses in the subnanometer range was surprising. Shimizu et al. discussed not only the qualitative detection of atoms of the organic monolayer (C, H, N, S), but also the determination of the different orientation of the molecules relative to the surface due to a significant peak sequence. This latter assumption was questioned in the analytical community. We intend to demonstrate the potential of the GD-OES technique for surface analysis in terms of reliability and reproducibility by using an advanced vacuum instrumentation and presputtering with silicon. It will be shown that comparable measurements can be reproduced not only with RF-GD-OES but, above all, also with DC-GD-OES. The experimental steps to adsorb thiourea molecules on a copper substrate are described in detail. Further experiments with other organic molecules, e.g. benzotriazole (BTA) or benzothiazole (BTH), disprove the predicted correlation between the orientation of the molecules relative to the surface and the occurrence of peak separation. Ultimately, a quantification of compounds of the organic monolayer in the case of adsorbed thiourea is achieved.FigureDC-GD-OES surface depth profiles of an adsorbed monolayer of thiourea