Using metallic noncontact atomic force microscope tips for imaging insulators and polar molecules: Tip characterization and imaging mechanisms

Link:
Autor/in:
Erscheinungsjahr:
2014
Medientyp:
Text
Schlagworte:
  • NC-AFM
  • imaging mechanism
  • insulator
  • metallic tip
  • virtual AFM
Beschreibung:
  • We demonstrate that using metallic tips for noncontact atomic force microscopy (NC-AFM) imaging at relatively large (>0.5 nm) tip surface separations provides a reliable method for studying molecules on insulating surfaces with chemical resolution and greatly reduces the complexity of interpreting experimental data. The experimental NC-AFM imaging and theoretical simulations were carried out for the NiO(001) surface as well as adsorbed CO and Co-Salen molecules using Cr-coated Si tips. The experimental results and density functional theory calculations confirm that metallic tips possess a permanent electric dipole moment with its positive end oriented toward the sample. By analyzing the experimental data, we could directly determine the dipole moment of the Cr-coated tip. A model representing the metallic tip as a point dipole is described and shown to produce NC-AFM images of individual CO molecules adsorbed onto NiO(001) in good quantitative agreement with experimental results. Finally, we discuss methods for characterizing the structure of metal-coated tips and the application of these tips to imaging dipoles of large adsorbed molecules.
Lizenz:
  • info:eu-repo/semantics/restrictedAccess
Quellsystem:
Forschungsinformationssystem der UHH

Interne Metadaten
Quelldatensatz
oai:www.edit.fis.uni-hamburg.de:publications/1f5fdcda-ecd8-4b5a-b7ea-33b55320a0a8