Minimum-contact Tapping-mode Atomic Force Microscopy for Nondestructive Characterization of Soft Nanostructures

用于软纳米结构无损表征的最小接触轻叩模式原子力显微镜sharry Dankowicz，弗吉尼亚理工学院和州立大学摘要原子力显微镜的发明为直接测量分子间力和在包括半导体、聚合物、碳纳米管和生物细胞在内的广泛材料中的原子精度地形测绘铺平了道路。在不同的成像方式中，间歇接触（TappingModeTM）原子力显微镜大大减少了对探针尖端的粘附和摩擦的影响。然而，在这里，接触间歇性的不稳定影响可能导致探针尖端振荡，具有高接触速度和破坏性，不可重复和不可靠的纳米结构表征。本研究旨在开发和实验证明最小接触、轻敲模式原子力显微镜的创新设计和控制策略的可行性，以成功和非侵入性地表征纳米级软物理结构。所提出的控制策略的成功应用有望显著提高结构扫描的可重复性，并提供更忠实的表面特性表示，同时显著减少对被测结构的损伤。通过与纳米尺度计量设备的领先供应商Veeco Instruments Inc.的正式合作，提供了与行业相关问题配方的直接联系和长期商业化渠道。这项研究工作还与研究人员的教育和推广活动相结合，通过将纳米尺度表征原理的模块纳入高年级本科和研究生一年级的课程“MEMS和NEMS建模”，并通过创建针对当地和区域高中的纳米尺度科学宣传手册。

Minimum-contact Tapping-mode Atomic Force Microscopy for Nondestructive Characterization of Soft NanostructuresHarry Dankowicz, Virginia Polytechnic Institute and State UniversityAbstractThe invention of the atomic force microscope has paved the way for direct measurements of intermolecular forces and atomic-precision topographical mapping in a wide array of materials including semiconductors, polymers, carbon nanotubes, and biological cells. Of the different imaging modalities, intermittent-contact (TappingModeTM) atomic-force microscopy greatly reduces the effects of adhesion and friction on the probe tip. Here, however, the destabilizing influence of the intermittency of contact may result in probe-tip oscillations with high contact velocity and destructive, nonrepeatable, and unreliable characterization of the nanostructure.This research effort aims to develop and experimentally demonstrate the feasibility of innovative design and control strategies for minimum-contact, tapping-mode atomic force microscopy to successfully and nonintrusively characterize soft physical structures at the nanoscale. Successful application of the proposed control strategies is expected to dramatically improve the repeatability of structure scans and to provide a more faithful representation of surface properties while significantly reducing damage to the measured structure.A direct link to industry-relevant problem formulations and a channel for long-term commercialization is provided through a formalized collaboration with Veeco Instruments Inc., a leading provider of nanoscale metrology equipment. This research effort is also integrated with educational and outreach activities of the investigators, through the inclusion of modules on principles of nanoscale characterization in the senior-level undergraduate and first-year graduate-level course "Modeling MEMS and NEMS" and through the creation of a promotional brochure on nanoscale science aimed at local and regional high schools.