In atomic force microscope based force spectroscopy, it is often necessary to minimize the tip-sample contact force. While it is possible to control the contact force using force feedback, this method is susceptible to sensor drift and is often under-utilized due to the noise associated with the feedback process. Here we present a method to control the tip-sample contact force for repeated pulling cycles without relying on force feedback or tedious user-controlled z-stage step increments. The custom pulling program uses the data recorded during the previous retraction cycle to automatically reposition the sample surface to account for changes in topography and system drift. Using this method we were able to complete 250 automated pulling cycles, 76% of which had evidence of tip-sample contact. Of those pulling cycles with tip-sample contact, the average contact force was 83 pN, with the maximum contact force not exceeding 292 pN.
- Design Engineering Division and Computers in Engineering Division
Minimizing Tip-Sample Contact Force in Automated Atomic Force Microscope Based Force Spectroscopy
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Rivera, M, Morris, C, Carlson, D, Toone, EJ, Cole, DG, & Clark, RL. "Minimizing Tip-Sample Contact Force in Automated Atomic Force Microscope Based Force Spectroscopy." Proceedings of the ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. Volume 6: ASME Power Transmission and Gearing Conference; 3rd International Conference on Micro- and Nanosystems; 11th International Conference on Advanced Vehicle and Tire Technologies. San Diego, California, USA. August 30–September 2, 2009. pp. 731-736. ASME. https://doi.org/10.1115/DETC2009-87378
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