A calibration error revealed via local tip position detection in atomic force microscopy

ORAL

Abstract

Atomic Force Microscopy (AFM) is a versatile tool in nanoscience. In conventional AFM, knowledge of the local 3D tip position is not accessible and tip trajectories are extrapolated from the cantilever deflection ($\Delta Z)$ which provides data of reduced dimensionality. The sensitivity (nm/V) of $\Delta Z$ is calibrated by taking slope of $\Delta Z $curve when the tip makes contact to a surface. Using a focused laser beam directly focused on the apex of the AFM tip, we have measured 3D positions of the tip as it interacts with a sample surface in fluid. We have observed a significant difference between the slope of ($\Delta Z)$ and that of the $Z$-tip position. This implies an erroneous calibration of sensitivity of $\Delta Z$ detection which we can now correct. Also, we have observed significant lateral slipping of tip as it touches the surface. These observations provide a comparison between tip and cantilever dynamics.

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Authors

  • Krishna Sigdel

    Department of Physics and Astronomy, University of Missouri-Columbia

  • Mark Neubauer

    University of Missouri-Columbia, Southern Illinois University Carbondale, Indiana University, Purdue University, Argonne National Laboratory, University of Missouri, College of Physics Science, Qingda University, Qingdao, 266071, China, Indian Institute of Science, Bangalore, India, University of Massachusetts Amherst, Iowa State University, Technical University of Denmark, University of Missouri - Columbia, University of California - San Diego, La Jolla, CA 92093, Department of Physics, University of Missouri-Columbia, Columbia, Missouri 65211, Department of Physics and Astronomy, University of Missouri-Columbia, University of Missouri, Columbia, MO, Department of Physics and Department of Biochemistry, University of Missouri, Columbia, MO 65211, Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, Univ of Missouri - Columbia, Duke University, Shanghai Jiaotong University, Ames Laboratory, U.S. DOE, Texas Center of Superconductivity and the Department of Physics, University of Houston, Institute of Physics, Siberian Division, Russian Academy of Sciences, Krasnoyarsk, 66036, Russia, Oak Ridge National Laboratory, NIST Center for Neutron Research, MU Research Reactor, Ames Laboratory and Dep. of Physics and Astronomy, Iowa State University, AmesAmes Laboratory and Dep. of Physics and Astronomy, Iowa State University, HFIR, Oak Ridge National Laboratory, University of Illinois at Urbana-Champaign