Primary AFM Imaging Modes:
Contact Mode (CM): high spatial resolution can be obtained, but may damage soft surfaces and adsorbed layers.
Tapping Mode (TM): In this case the topography can be obtained by lightly tapping the surface with the oscillating probe. This mode is less destructive to the surface as compared to contact mode. It is the most used of all AFM modes.
Imaging in fluid is available in both modes, Contact and Tapping.
Torsion Resonance Mode (TR): is new technique that measures and controls dynamic lateral forces between the AFM probe and sample surface. This mode allows working close to the surface without actually contacting it, providing both high spatial resolution, and options for close range measurements (such as TUNA and lateral magnetic force imaging).
Secondary AFM imaging modes:
Lateral Force Microscopy: provides information on variations of the local friction.
Phase Microscopy: derived from TM and detects variations in composition, adhesion, friction, visco-elasticity, and as well as edge detection.
Conductive Atomic Force Microscopy (C-AFM): measurement of the local conductivity variations across medium of conductive samples with the lateral resolution of a few nanometers. C-AFM has a current range of picoA to microA.
Tunneling-AFM (TUNA): Similar to C-AFM, but with ultra-low current measurement capability, between 80 fA to 120 pA.
Magnetic Force Microscopy (MFM): maps magnetic force gradient above the sample surface, with a special magnetic tip. This mapping is performed via two-pass technique, LiftMode.
Electric Field Microscopy (EFM): similar to MFM, measures electric field gradient distribution above the sample. Voltage is applied between tip and sample.
Surface Potential Imaging: maps the variation of the electrostatic potential across the sample surface.
Scanning Capacitance Microscopy (SCM): maps variations in majority electrical carrier concentration (electrons or holes) across the sample surface, typically a doped semiconductor.
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Force Imaging:
Force modulation: can be used for imaging local sample stiffness or elasticity..
Force Spectroscopy: provide information on the tip-surface adhesion, hardness and local elasticity of the sample.
Force Volume: combines force measurement and topographic imaging capabilities. Possible applications include elasticity, adhesion, electrostatic, magnetic and binding studies.
Non-imaging modes:
Spectroscopy: Force spectroscopy, I-V curve.
Force Spectroscopy: produces force vs. distance curve, is used to analyze the adhesion of surface contaminations, as well as local variations in the elastic properties.
Nanolithography: is "drawing" a nanometric-scale pattern on a sample surface by using an SPM probe.
Scratching - mechanically scribing the surface by applying excessive force with an AFM tip.
Oxidation - by applying highly localized electric fields with AFM tip.
Nanomanipulation: allows direct, precise manipulation of nanoscale objects, such as nanotubes and nanoparticles in the plane of the sample surface.
Nanoindentation: is a way to measuring mechanical properties, such as hardness and Young's Modulus, by nanoindenting a sample with an AFM tip.
Signal Access Module (SAM):
Designed to give researchers the open architecture they need to conduct innovative experiments. SAM is provided for up to 35 input/output separate SPM signals through BNC connectors. |