Atomic Force Microscopy (AFM) is a technique that allows to visualize with a nanometric resolution the three-dimensional morphology of the surface of a material, and to map some of its properties (adhesive, mechanical, magnetic, electrical, ...). This technique allows the observation of the surfaces of all types of solid materials (polymers, powders, glasses, textiles, fibers, biological samples, nanoparticles...) in air and in liquid medium at atmospheric pressure.

AFM allows you to image the surfaces of all types of solid materials as well as their physical properties at the nanometric scale. 

The principle of AFM is based on the measurement of the different interaction forces (ionic repulsion forces, Van-der-Waals forces, electrostatic forces, etc...) between the atoms of the surface of the sample to be observed and the atoms of a nanometric probe tip, fixed under a flexible microlever. A laser beam, reflected on the back side of the microlevier and directed on a 4 quadrants photodiode. The tip scans the surface and follows the topography of the sample, giving a three-dimensional image of the analyzed material. This image allows in particular to calculate the roughness parameters.

Different types of probes can be used to obtain a qualification and a quantification of the various physical properties of the surface.

 

NEW - AFM IR

Coupling the spatial resolution of AFM with the chemical analysis capabilities of IR in order to locate compounds with the ~20 nm resolution of AFM thanks to their IR signature.

CONTACT MODE

Acquisition of a three-dimensional topographic image
The deflection of the microlever is maintained constant by a servo loop while the sample is moved in X, Y and Z. 

TAPPING MODE

Simultaneous measurement of the 3D topography and viscoelastic parameters of the surface
The tip oscillates close to its resonance frequency and scans the surface at constant amplitude. The phase shift between the sinusoid applied to the tip and the one acquired on the photodiodes is dependent on the viscoelastic properties of the surface and gives an image often more detailed than the topography.

PEAK FORCE TAPPING AND QNM MODE

Simultaneous measurement of 3D topography and mechanical parameters
The force applied on the tip is controlled to preserve the sample and the AFM point. The approach-shrinkage curves at 2 kHz are obtained (force spectroscopy) and analyzed in real time in order to extract the mechanical parameters (Young's modulus, tip-surface adhesion, deformation...). After calibration of the tip, the measurements become quantitative.

CONDUCTIVE ATOMIC FORCE MICROSCOPY MODE

Simultaneous acquisition of 3D topography and current mapping of a surface
A potential difference (VDC) is applied between the sample and the mass (or the tip and the mass) to measure the current flowing from the tip to the sample.

SCANNING CAPACITANCE MICROSCOPY MODE

Simultaneous acquisition of 3D topography and charge carrier concentration mapping (discrimination of n and p dopants as well as low and high doping levels)
A potential difference (VAC) is applied between the tip and the sample to measure the capacitance change between the tip and the sample thanks to an ultra sensitive high frequency resonant circuit.

SCANNING SPREADING RESISTANCE MICROSCOPY MODE

Simultaneous acquisition of 3D topography and charge carrier density mapping
A potential difference (VDC) between the tip and the sample is applied. The spreading resistance (and thus the charge carrier density) is measured by applying a large force on the tip combined with the use of a broadband amplifier.

KELVIN PROBE FORCE MICROSCOPY MODE

Two-pass acquisition of 3D topography and surface potential mapping
A potential difference (VDC) is applied between the tip and the sample to compensate the difference in vacuum levels.

TRACTION MODULE

Study of the cracking or deformation of a coating on a flexible substrate.
The characteristics of the traction plate are the following: 
- Adjustable jaw spacing speed from 0.8 mm/min to 25 mm/min.

- Force sensor (range 0-500 N), accuracy 0.1 N.

- Displacement sensor (range 50 mm), accuracy 0.01 mm
 

AFM technical specifications

• Maximum accessible area: 110 × 110 µm² (z-variation 14 µm maximum).
  Image stiching is a possibility to observe larger areas. To observe larger areas and requiring a larger z-shift, the use of an optical profilometer is preferred.
• ​Vertical resolution: 0.1 Å
• Lateral resolution/Probe size: 2 - 150 nm

AFM strenghts

• Quantification of surface roughness at the nanoscale
• High spatial resolution
• Imaging of fragile samples (nanoparticles, cells, proteins...)
• Imaging of conductive and insulating samples
• Imaging at atmospheric pressure or in liquid media
• Analysis of wafers up to 300 mm