Atomic Force Microscope

Description:

The heart of the AFM is the cantilever and tip assembly, which is scanned with respect to the surface. Any morphological feature of the surface causes a movement of the tip in the xyz direction which means a change of the deflection angle of the laser beam. This change is measured through a photodiode and translated finally to an image, as shown in the figure below.

The physical principle of AFM is the intermolecular and surface forces, asked between the surface and the tip, which are distance depended. These forces are responsible for the movement of the cantilever.

Description:

The Atomic Force Microscope (AFM) provides the ability:

  • to acquire three-dimensional images with angstrom resolution from conducting and nonconducting surfaces, in air and in liquid environment
  • to be used as a nanoscale surface force apparatus to measure adhesion between materials and the indentation/deformation properties of surfaces under extremely small loads.

Besides the use of AFM for imaging the morphology of surfaces, it is also used, nowdays in MTM, for two research projects:

  • the in-situ electrodeposition of metal coatings and the characterisation of the structure of the coating.
  • the direct measurement of colloidal forces, between a particle and a flat surface, in order to get insight in process of codeposition of submicron particles into a metal matrix.

Technical details:

Microscope:
- Standard top view contact AFM microscope
- ScannerX-Y range
Z range		 atomic resolution up to 13µm
atomic resolution up to 2.68µm
- Lateral Force Mode (LFM) head
- Electrochemical AFM (ECAFM) head

Sample size:
- Up to 15mm diameter and up to 5mm thick

Tips/Cantilever:
- Oxide sharpened silicon nitride probes with gold reflective coating
- Spring constants from 0.02N/m to 0.7N/m

Vibration isolation:
- Passive demping with heavy stone and elastics cords
- Silicon vibration pad

Nanoscope III controller:
- Simultaneous capture and display up to 512x512 resolution
- X,Y and Z scanner drives, each 220V range, three independant 16-bit D/A converters for scan pattern, scaling and offset. X-Y electronic noise <1mV peak-to-peak for 10V scan offset.

Computer:
- Intel brand 66MHz CPU with 12Mb RAM, 200 Mb hard disk for program and 1.2Gb hard disk for data
- Optical disk drive 230Mb floppy
- Twin 15” color control and image display monitors
- High resolution video display

Optical microscope for tip and sample:
- 450x optical viewing with B/W CCD camera and monitor

 
Room: 01.01

 
More Technical information: Techinfo@mtm.kuleuven.be
 

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Last modified: January, the 18th, 2002