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

最小接触轻敲模式原子力显微镜的非破坏性表征的软nanostructuresHarry 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铺平了道路，直接测量分子间的力量和原子精度的拓扑映射在广泛的材料，包括半导体，聚合物，碳纳米管和生物细胞。在不同的成像方式中，非接触式（TappingModeTM）原子力显微镜极大地减少了探针尖端上的粘附和摩擦的影响。然而，在这里，不稳定的影响，接触的不稳定性可能会导致探针尖端振荡与高接触速度和破坏性的，不可重复的，和不可靠的表征nanostructure.This研究工作的目的是开发和实验证明的可行性，创新的设计和控制策略，为最小接触，双模态原子力显微镜成功地和非侵入性地表征纳米级的软物理结构。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，同时显著减少对测量结构的损坏。通过与Veeco Instruments Inc.纳米计量设备的领先供应商。这项研究工作还与研究人员的教育和宣传活动相结合，通过在高级本科和研究生一年级课程“MEMS和NEMS建模”中纳入纳米尺度表征原理模块，并通过针对地方和区域高中制作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.