1. STM / AFM Images Explanations from
2. Scanning Tunneling Microscopy In 1981, the Scanning Tunneling microscope was developed by Gerd Binnig and Heinrich Rohrer – IBM Zurich Research Laboratories in Switzerland (Nobel prize in physics in 1986).
This instrument works by scanning a very sharp metal wire tip over a sample very close to the surface. By applying an electric current to the tip or sample, we can image the surface at an extremely small scale – down to resolving individual atoms.
5. The number of electrons that will actually tunnel is very dependent upon the thickness of the barrier. The actual current through the barrier drops off exponentially with the barrier thickness.
To extend this description to the STM: The barrier is the gap (air, vacuum, liquid) between the sample and the tip. By monitoring the current through the gap, we have very good control of the tip-sample distance.
6. Computer software is used to add color and analyze the captured data.
7. SCAN IMAGE DEMONSTRATE ANALYSIS Use images from Science Express laptop.
8. Diffraction Grating
9. 3-D View: Diffraction Grating
10. Diffraction Grating - Analysis
11. Red Blood Cells
12. Red Blood Cells – Analysis
14. 3-D View : Graphite
15. Graphite - Analysis
16. Graphite - magnified
17. Graphite - magnified
18. Graphite - magnified
19. Graphite – magnified – AGAIN!
21. Graphite – magnified – AGAIN!
22. Purdue University Physics Department http://www.physics.purdue.edu/nanophys/stm.html
25. Atomic Force Microscopy In principle, the AFM works like the stylus on an old record player.
There is actual contact between the probe tip and the sample.
26. Atomic Force Microscopy
27. Atomic Force Microscopy
28. AFM IMAGES http://jpk.com/spm/gallery1.htm
33. …science has helped us see in fine detail…