The working principle of the AFM is as follows: A point laser hits the cantilever and reflected laser beam is centred on to the quadrant position sensitive photodetector (PSPD). When the cantilever tip encounters any feature on the sample surface while scanning, will deflect the laser falling on the quadrant PSPD. This deflection is then given as a feedback to the cantilever to move the cantilever and then the laser spot back to the previous zero position. Consequently, the tip will be kept at a constant distance from the sample surface. By recording the position of the motor height, we will be able to map the topography of the sample surface.
The AFM at Kjemisk Institute at UiO is a Park systems XE-70 model Scanning Probe Microscopy tool. Park systems feature decoupled flexure-guided X, Y and Z scanners with zero background curvature. The Z-servo response is also considerably higher than that of conventional tube scanners, thus enabling true Non-Contact mode. The machine accommodates samples up to 100 mm in diameter and has a maximum scan size of 50 X 50 μm (5 X 5 μm in low-voltage mode). The Z range is 12 μm (1.7 μm in low-voltage mode). XY resolution 0.15nm and Z resolution is 0.05nm. The XE-70 setup includes direct on-axis optics with manual Z focus stage.
The XE-70 can be utilized for a different mode including,
- Contact mode AFM
- Non-contact AFM
- Lateral Force Microscopy
- Force Distance Spectroscopy
- Electric Force microscopy ( C-AFM, PFM, KPFM)
- Magnetic Force microscopy.
For further information or inquiries, please contact Ola Nilsen.