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Non-contact atomic force microscopy (nc-AFM), also known as dynamic force microscopy (DFM), is a mode of atomic force microscopy, which itself is a type of scanning probe microscopy. In nc-AFM a sharp probe is moved close (order of Angstroms ) to the surface under study, the probe is then raster scanned across the surface, the image is then ...
The AFM can be operated in a number of modes, depending on the application. In general, possible imaging modes are divided into static (also called contact) modes and a variety of dynamic (non-contact or "tapping") modes where the cantilever is vibrated or oscillated at a given frequency. [8]
The non-contact feedback loop is used to control that changes in the oscillations of the cantilever. [37] The application of AFM on non-conducting samples (c-AFM) has in recent years evolved into the modification used for analysis of morphologies on the local scale, particularly morphologies at heterojunctions of multilayered samples.
On the left is the control unit with lock-in amplifier and backing potential controller. On the right is the x, y, z scanning axis with vibrator, electrometer and probe mounted. Kelvin probe force microscopy (KPFM), also known as surface potential microscopy, is a noncontact variant of atomic force microscopy (AFM).
This interaction depends on the type of SPM, for scanning tunneling microscopy the interaction is the tunnel current, for contact mode AFM or MFM it is the cantilever deflection, etc. The type of feedback loop used is usually a PI-loop, which is a PID-loop where the differential gain has been set to zero (as it amplifies noise).
The first mode relies on the AFM contact mode, and the second mode of operation employs a scanning thermal microscopy probe (invented in 1986 [20]) to measure the polymer's temperature increase. In 2007, AFM was combined with infrared attenuated total reflection (IR-ATR) spectroscopy to study the dissolution process of urea in a cyclohexane ...
In this mode the cantilever is oscillated at a resonant frequency of the cantilever and the AFM tip is held such that it only senses with long range electrostatic forces without entering the repulsive contact regime. In this non-contact regime, the electric force gradient causes a shift in the resonance frequency of the cantilever.
Researchers have developed an array of operating modes and methods for Scanning probe microscopy and Atomic Force Microscopy. The use and application of such methods requires SPM or AFM instruments equipped with method-specific SPM or AFM probes. Nanosensors supplies SPM or AFM users worldwide with a range of such method-specific SPM or AFM ...