Nano-mechanics: Atom resolved AFM and Nanoimprint Lithography

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• J.B.Pethica, Trinity College Dublin, Ireland
• Friday 02 February 2007, 15:30-16:30
• IRC in Superconductivity Seminar room.

If you have a question about this talk, please contact spl37.

This talk will describe two new experimental areas in Nano-mechanics. Recent improvements in signal to noise for small (<0.05nm) amplitude AFM now enable routine recording of force gradient and tunnel current simultaneously at atomic resolution. This eliminates the uncertainty of position between force and current which arises in separate imaging. Results for Si(111), TiO2(110) and Cu(100) surfaces will be shown. Comparison of constant height and constant current images shows that local electrostatic forces may be substantial even for Si, and that long range forces are less significant than previously thought. For oxides, the polarity of the tip can be determined directly from the registry (anion vs cation) between force and current, giving a potentially powerful new local charge sensing method. Imprint lithography(the formation of patterns by mechanical stamping into a soft material) has nanometre resolution, high throughput and low cost. We have used nanoindentation methods to understand the residual film and hence mask ratio limitations of normal loading. these are mainly due to elastic strains. It will be shown that a small amplitude shear oscillation provides a remarkable increase in mass transport, preserves full nm fidelity and has important scaling advantages in manufacture. Finite element modelling clarifies the novel inelastic pumping mechanism involved, and the surprising relative insensitivity to interfacial friction conditions.

This talk is part of the Nanoscience Centre Seminar Series series.

This talk is included in these lists:

• IRC in Superconductivity Seminar room
• All Talks (aka the CURE list)
• Cambridge Infectious Diseases
• Dobson Group - General Interest
• Nanoscience Centre Seminar Series
• School of Physical Sciences
• School of Technology

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