Related Experiment Video
Updated: Apr 30, 2026
12:58
Characterizing Individual Protein Aggregates by Infrared Nanospectroscopy and Atomic Force Microscopy
Published on: September 12, 2019
9.4K
Using metallic noncontact atomic force microscope tips for imaging insulators and polar molecules: tip
David Zhe Gao1, Josef Grenz, Matthew Benjamin Watkins
1Department of Physics and Astronomy, University College London , Gower Street, London WC1E 6BT, United Kingdom.
ACS Nano
|May 3, 2014
Summary
Metallic tips enable chemical resolution in noncontact atomic force microscopy (NC-AFM) for molecules on insulating surfaces. This method simplifies data interpretation and accurately images molecular dipoles.
Area of Science:
- Surface Science
- Chemical Physics
- Materials Science
Background:
- Noncontact atomic force microscopy (NC-AFM) is crucial for molecular imaging.
- Interpreting NC-AFM data for molecules on insulating surfaces can be complex.
- Metallic tips offer potential for enhanced chemical resolution.
Purpose of the Study:
- To demonstrate metallic tips for high-resolution NC-AFM imaging of molecules on insulating surfaces.
- To investigate the role of tip-surface separation in chemical resolution.
- To simplify the interpretation of NC-AFM experimental data.
Main Methods:
- Experimental NC-AFM imaging using Cr-coated Si tips.
- Theoretical simulations using density functional theory (DFT).
- Analysis of tip-surface interactions at large tip-surface separations (>0.5 nm).
Main Results:
- Metallic tips exhibit a permanent electric dipole moment oriented towards the sample.
- The dipole moment of Cr-coated tips was determined experimentally.
- A point dipole model accurately reproduced experimental NC-AFM images of CO molecules on NiO(001).
Conclusions:
- Metallic tips provide reliable chemical resolution for NC-AFM of molecules on insulators.
- The dipole moment of the metallic tip is key to understanding imaging mechanisms.
- This approach facilitates the characterization of molecular dipoles and tip structures.
