In the last 30 years research has shown that the resolution and reproducibility of data acquired using the atomic force microscope (AFM) can be improved through the development of new imaging modes or by modifying the AFM tip. One method that has been explored since the 1990s is to attach carbon nanotubes (CNT) to AFM tips. CNTs possess a small diameter, high aspect ratio, high strength and demonstrate a high degree of wear resistance. While early indications suggested the widespread use of these types of probes would be routine this has not been the case. A number of methods for CNT attachment have been proposed and explored including chemical vapor deposition (CVD), dielectrophoresis and manual attachment inside a scanning electron microscope (SEM). One of the earliest techniques developed is known as the pick-up method and involves adhering CNTs to AFM tips by simply scanning the AFM tip, in tapping mode, across a CNT-covered surface until a CNT attaches to the AFM tip. In this work we will further investigate how, for example, high force tapping mode imaging can improve the stability and success rate of the pick-up method. We will also discuss methods to determine CNT attachment to AFM probes including changes in AFM image resolution, amplitude versus distance curves and SEM imaging. We demonstrate that the pick-up method can be applied to a range of AFM probes, including contact mode probes with relatively soft spring constants (0.28 N/m). Finally, we demonstrate that the pick-up method can be used to attach CNTs to two AFM tips simultaneously. This is significant as it demonstrates the techniques potential for attaching CNTs to multiple AFM tips which could have applications in AFM-based data storage, devices such as the Snomipede, or making CNT-AFM tips more commercially viable.

中文翻译：

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使用拾取方法将碳纳米管附着到原子力显微镜吸头上

在过去的30年中，研究表明，通过开发新的成像模式或修改AFM尖端，可以提高使用原子力显微镜（AFM）采集的数据的分辨率和可重复性。自1990年代以来一直在探索的一种方法是将碳纳米管（CNT）连接到AFM尖端。CNT具有小直径，高长宽比，高强度并显示出高度的耐磨性。尽管早期迹象表明，通常会广泛使用这些类型的探针，但实际情况并非如此。已经提出并探索了许多用于CNT附着的方法，包括化学气相沉积（CVD），介电电泳和在扫描电子显微镜（SEM）内的手动附着。最早开发的技术之一就是拾取方法，该技术涉及通过以轻敲模式在覆盖CNT的表面上简单扫描AFM尖端，直到CNT附着在AFM尖端上，从而将CNT粘附到AFM尖端上。在这项工作中，我们将进一步研究例如强力攻丝模式成像如何提高拾取方法的稳定性和成功率。我们还将讨论确定CNT附着在AFM探针上的方法，包括AFM图像分辨率，幅度与距离的关系曲线以及SEM成像的变化。我们证明了拾取方法可以应用于一系列AFM探头，包括具有相对较软的弹簧常数（0.28 N / m）的接触模式探头。最后，我们证明了拾取方法可用于将CNT同时连接到两个AFM尖端。