High-speed atomic force microscope imaging: adaptive multiloop mode.
High-speed atomic force microscope imaging: adaptive multiloop mode.
复制标题
高速原子力显微镜成像：自适应多环模式。
DOI：
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发表时间：
2014
期刊：
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通讯作者：
Zhiqun Lin
中科院分区：
文献类型：
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作者：
Juan Ren;Q. Zou;Bo Li;Zhiqun Lin
在本文中，提出了一种原子力显微镜（AFM）的成像模式（称为自适应多旋转模式），以实质上提高敲击模式（TM）成像的速度，同时保留TM成像比接触模式（CM）成像的优势。由于其优越的图像质量和较少的样品灾害，尤其是对于诸如聚合物之类的软材料，TM成像是当前最广泛的成像技术。然而，由于必须维持稳定的探针敲击，因此挑战了TM成像的速度，因此比CM成像低（超过数量级），成为该技术的主要瓶颈。质量，而探针的攻击对样品地形的变化很敏感。图像失真和/或样品变形。拟议的自适应多旋转模式（AMLM）成像通过以下三个努力整合在一起，克服了TM成像的这些局限性：首先，提出了TM的变化第二，在敲击反馈控制循环的顶部添加了一个内部的反馈控制循环，以改善样本地形；将馈电控制器增强到整个控制系统中，以进一步增强地形跟踪，其中预测并利用了下一行样品地形，以减少跟踪误差。通过在实验中测试了稳定的探针样本相互作用的最小值结果表明，通过使用提出的AMLM成像以25 Hz的扫描速率和大尺寸成像（50μm×25μm）在使用TM成像以1 Hz获得的相同水平的相同水平，而在1 Hz中获得的图像质量达到的图像质量质量质量。探针样本相互作用的相互作用将与使用TM成像在2.5 Hz下实现的相互作用降低。
In this paper, an imaging mode (called the adaptive multiloop mode) of atomic force microscope (AFM) is proposed to substantially increase the speed of tapping mode (TM) imaging while preserving the advantages of TM imaging over contact mode (CM) imaging. Due to its superior image quality and less sample disturbances over CM imaging, particularly for soft materials such as polymers, TM imaging is currently the most widely used imaging technique. The speed of TM imaging, however, is substantially (over an order of magnitude) lower than that of CM imaging, becoming the major bottleneck of this technique. Increasing the speed of TM imaging is challenging as a stable probe tapping on the sample surface must be maintained to preserve the image quality, whereas the probe tapping is rather sensitive to the sample topography variation. As a result, the increase of imaging speed can quickly lead to loss of the probe-sample contact and/or annihilation of the probe tapping, resulting in image distortion and/or sample deformation. The proposed adaptive multiloop mode (AMLM) imaging overcomes these limitations of TM imaging through the following three efforts integrated together: First, it is proposed to account for the variation of the TM deflection when quantifying the sample topography; second, an inner-outer feedback control loop to regulate the TM deflection is added on top of the tapping-feedback control loop to improve the sample topography tracking; and, third, an online iterative feedforward controller is augmented to the whole control system to further enhance the topography tracking, where the next-line sample topography is predicted and utilized to reduce the tracking error. The added feedback regulation of the TM deflection ensures the probe-sample interaction force remains near the minimum for maintaining a stable probe-sample interaction. The proposed AMLM imaging is tested and demonstrated by imaging a poly(tert-butyl acrylate) sample in experiments. The experimental results demonstrate that the image quality achieved by using the proposed AMLM imaging at a scan rate of 25 Hz and over a large-size imaging (50 μm × 25 μm) is at the same level of that obtained using TM imaging at 1 Hz, while the probe-sample interaction force is noticeably reduced from that achieved using TM imaging at 2.5 Hz.