| AVS 60th International Symposium and Exhibition | |
| Scanning Probe Microscopy Focus Topic | Thursday Sessions |
| Session SP+AS+BI+EM+MI+NS+SE+SS-ThA |
| Session: | Probe-sample Interactions, Nano-manipulation and Emerging Instrument Formats |
| Presenter: | M. Miles, University of Bristol, UK |
| Authors: | M. Miles, University of Bristol, UK R. Harniman, University of Bristol, UK D.J. Phillips, University of Bristol, UK L.M. Picco, University of Bristol, UK O. Payton, University of Bristol, UK M. Antognozzi, University of Bristol, UK S. Simpson, University of Bristol, UK S. Hanna, University of Bristol, UK D.J. Engledew, University of Bristol, UK G. Gibson, University of Glasgow, UK R. Bowman, University of Glasgow, UK M.J. Padgett, University of Glasgow, UK |
| Correspondent: | Click to Email |
AFM offers unique characteristics amongst microscopy techniques, and offers many benefits such has high-resolution 3D imaging in many environments including liquids. However, there are three areas in which conventional AFM has limitations: (i) a low imaging rate, (ii) the probe-sample force interaction, and (iii) the planar nature of the sample. We are developing two high-speed force microscopy techniques to overcome the first two of these, (i) and (ii).
(i) One high-speed AFM (HS AFM) technique is a DC mode in which an automatic feedback mechanism essentially arising from the hydrodynamics of the situation maintains a tip-specimen separation of about 1 nm. This technique routinely allows video-rate imaging and has achieved imaging at over 1000 fps. Damage to specimens resulting from this high-speed DC-mode imaging is surprisingly less than at normal speeds. The behavior of the cantilever and tip at these high velocities has been investigated and super lubricity is a key component in the success of this technique [1,2].
(ii) The second high-speed force microscope is a non-contact method based on shear-force microscopy (ShFM). In this HS ShFM, a vertically-oriented, laterally-oscillating probe detects the sample surface at about 1 nm from it as a result of the change in the mechanical properties of the water confined between the probe tip and the sample. With this technique, very low normal forces are applied to the specimen. Information on the molecular water layers as a function of position [3,4].
(iii) AFMs require planar samples because the probe scans in a plane. The tip only ‘sees’ the sample from above. We have overcome this limitation by steering the tip of a nanorod in a three dimensional scan with six degrees of freedom using holographically generated traps such that it is possible to scan around a sample from any direction. We use various probe types: including silica nanorods, rod-like diatoms, and two-photon polymerized 3D structures [5,6].
1. Payton, OD, et al., Nanotechnology 23 (2012) Art. No. 265702.
2. Kalpetek, P, et al., Measurement Sci. & Technol., 24 (2013) Art. No. 025006.
3. Harniman RL, et al., Nanotechnology 23 (2012) Art. No. 085703.
4. Fletcher, J, et al., Science 340 (2013) online April 11th.
5. Phillips DB, et al., Nanotechnology 22 (2011) Art. No. 285503.
6. Olof SN et al., Nano Letters 12 (2012) 6018-6023.