Atomic Force Microscope
Contents
Atomic Force Microscopy (AFM)
also known as
Scanning Force Microscopy (SFM)
Theory
The resolution of the AFM is 1000 times better than an optical or light microscope which is limited by the wavelength of light. The AFM can resolve images to within a fraction of a nanometer. We use the MadcityLabs Nano-OPH Series nano-positioners. They have a range of motion up to 30μm, and a resolution of .06nm. The Resonant Frequency of the apparatus is 3.5kHz ± 20%, alowing up to a .5kg sample. [1]
Non-Contact mode
Our AMF works without coming in physical contact with the sample, commonly refered to as non-contact mode. the cantilever oscillates near the resonant frequency, with an amplitude of <10nm due to van der Waals forces operating within an nanometer to 10 nm above the surface of the sample.This interaction decreases the resonance frequency of the cantilever and adjusts the tip-to-sample distance. This provides a surface map of the sample
Apparatus
The AFM consists of 6 major parts. The apparatus includes a laser mounted vertically pointing down on the a platform mounted a PTZ scanner, or nano-drive, and a photodiode positioned to receive the reflected laser beam. The Probe is mounted above the platform where the sample surface lies, and contains a cantilever and tip which interact with the sample surface reflecting the laser beam into the photodetector
- AFM Operiation Diagram from wikipedia.svg
Atomic Force Microscope Block Diagram; Public Domain
