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Glossary terms about Force

Force
Can be attractive or repulsive between the probe and the sample.

▼2 more terms contain Force



23 pages mention Force

Additional material
 
AFM calibration methods
S. Scanning force microscopy - Calibrative procedures for 'best practice'. 
AFM imaging of surfaces
Journal Link... Bellucci, S., Gaggiotti, G., et al. Atomic force Microscopy Characterization of Carbon Nanotubes. 
AFM imaging: Interactions between the probe and sample
At very close tip-sample distances (a few angstroms), a strong repulsive force appears between the tip and the sample surface due to the overlap of atomic orbitals. 
AFM papers
F., et al. Atomic force Microscope. 
AFM probe modification
T., Carnally, S., et al. Attachment of carbon nanotubes to atomic force microscope probes. 
AFM: Background information
The Atomic force Microscope (AFM) operates by scanning an AFM probe across a sample surface. 
Contact and tapping modes
In the repulsive regime, small changes in distance give large changes in force and hence cantilever position. 
Contact mode
Contact mode/ constant force AFM operates by scanning the tip across the sample surface while monitoring the change in cantilever deflection with a split photodiode detector. 
Force distance spectroscopy
-J., Cappella, B., et al. force measurements with the atomic force microscope: Technique, interpretation and applications. 
How is the Data Displayed?
This data can range from tunneling current, to force between sample and tip, to height to reach a certain force etc. 
Image artefacts
The disadvantage of smaller diameter probes is that the pressure applied to the surface and the tip increases for a given imaging force
Introduction
Each member of this family uses a different type of interaction or force between the probing tip and the sample. 
Laser alignment on cantilever
If not performed properly then a number of artefacts can result including, for example, excessive force being applied to the surface when scanning and optical interference fringes from reflective surfaces can be detected. 
Measuring forces in the tip-sample space
In addition to imaging the surface of samples, another major application of AFM is force spectroscopy. 
Non-contact mode
In non-conact mode the attractive forces are weak (see Figure 8 previous page), and the technique is sensitive to external vibration. 
Non-contact mode
As the name implies, the (oscillating) tip is set further from the sample surface where it is surrounded by attractive forces, and the tip does not contact the surface at any stage. 
Review articles
-J., Cappella, B., et al. force measurements with the atomic force microscope: Technique, interpretation and applications. 
Set point - Tapping mode
In this case lowering the amplitude set-point will increase the tapping force exerted on the sample, and increasing the amplitude set-point will reduce the tapping force
Set-point - contact mode
Since the force the cantilever exerts on the sample is directly proportional to the deflection of the cantilever via Hooke’s Law, it is possible for the operator to control the amount of force being applied to the sample surface while imaging. 
Tapping mode
Tapping mode has a number of advantages compared with contact mode, including greatly reduced lateral and normal forces being applied to the sample surface. 
Techniques
There are many varieties of scanning probe microscope (SPM) techniques ranging from the most common which are atomic force microscopy (AFM) and scanning tunnelling microscopy (STM), to more specialised instruments such as the near-field scanning optical microscope (NSOM/SNOM), tip-enhanced Raman microscope (TERS), and lateral force microscope (LFM) among others. 
Tip artefacts
The tip may be worn down due to excessive imaging or using excessive force