|
|
| Line 42: |
Line 42: |
|
| |
|
| The technique can be used for different purposes: | | The technique can be used for different purposes: |
|
| |
|
| |
| ===Chemical state===
| |
|
| |
|
| |
| [[image:Si2p.JPG|420x420px|left|thumb|XPS Si2p spectrum of a Si reference sample (red curve), and a Si sample that was treated in HF shortly before the measurement was done (green curve). ]]
| |
| Due to the so called chemical shift, it is possible to get information about the chemical state of the probed atoms.
| |
| The core electrons of the atoms are affected, meaning that the binding energy of the electrons are slightly shifted, when an atom is bonded to atoms of other elements.
| |
|
| |
| This gives an excellent tool for examining the chemistry of a surfaces, and how it is affected by different surface treatments.
| |
|
| |
| The figure to the left gives an illustration of the effect. An XPS Si2p spectrum of a Si reference sample and a Si sample that was treated in HF shortly before the measurement, is clearly showing two different curves. The untreated spectrum has a clear feature at about 103 eV due to Si atoms bonded to oxygen. In the spectrum from the HF treated sample, only the feature steaming from Si-Si interaction is present. Note that both curves only shows the Si signal, but with an clear indication of the chemical state of the Si atoms in the samples.
| |
|
| |
| If you study polymers, you can detect the presence of different chemical groups, for example (C-C),(C-OH),(C=O),(CF3) or (CF2-CH2) in the polymeric layer. And after surface treatments, you may examine differences in the polymeric layer.
| |
|
| |
| Note that binding energies for different chemical states often can be found in the literature.
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
| |
|
|
| |
|
