Dear Colleague Burlu,

X-Ray photoelectron spectroscopy, XPS was used to investigate the chemistry at the surface of the samples. The basic mechanism behind an XPS instrument is that  the photons of a specific energy are used to excite the electronic states of atoms at and just below the surface of the sample.

There are several areas suited to measurement by XPS:

1. Elemental composition

2. Empirical formula determination

3. Chemical state

4. Electronic state

5. Binding energy

6. Layer thickness in the upper portion of surfaces

XPS has many advantages, such as  it is is good for identifying all but two elements, identifying the chemical state on surfaces, and is good with quantitative analysis. XPS is capable of detecting the difference in chemical state between samples. XPS is also able to differentiate between oxidations states of molecules.

XPS  has also some limitations, for instance, samples for XPS must be compatible with the ultra high vacuum environment.  XPS is limited to measurements of elements having atomic numbers of 3 or greater, making it unable to detect hydrogen or helium. XPS spectra also take a long time to obtain. The use of a monochromator can also reduce the time per experiment. 

Hope this helping

Have a very good day

A typical XPS can determine the % composition (.1-1% minimum is typically quoted) and chemical states of the constituent species those are the typical first experiments that are performed. There is also a lot to be said for the actual specs of the instrument as to what you'll be able to see/distinguish. I would suggest saying what information you would like to know and then find a technique(s) to fit that.

Although this is comercial stuff, it gives you some hints on what you can expect from XPS

http://www.research.philips.com/technologies/matanalysis/downloads/3-xpstn.pdf

http://www.vgscienta.com/_resources/File/MX650%20data%20sheet%20v4.1web.pdf

Or at wiki,

http://en.wikipedia.org/wiki/X-ray_photoelectron_spectroscopy

I think we can find the oxidation states of respective elements through XPS

XPS gives the composition (ratio O/Ti = 2/1 in the case of TiO2)... but more important is the sensitivity of the technique to the chemical environment of the atoms... O1s line would have a given binding energy for oxygen atoms bound to Ti atoms and a different binding energy for oxygen atoms of moisture adsorbed on the surface... You have also to keep in mind that XPS is a SURFACE TECHNIQUE... The depth probed by the technique is few nanometers! It depends basically on the energy of the photoelectrons detected... less kinetic eenrgy ( i.e higher binding energy ), less depth is probed... 5nm is a typical depth..Therefore do not be surprised to see intense peaks of carbon and oxygen from a sample even if it is not supposed to contain any..! (these are atoms of the contamination layer resulting from the exposure of the sample to ambiant atmosphere before analysis)... XPs instruments are ussually equipped with LN2 cooled fracture stages to break the samples under high vacuum so that fresh surfaces can be analyzed... Ion guns are also used to remove the contamination layer (but can induce unwanted changes in the sample) .. They are also used to measure depth profiles (.e. variation of composition versus depth)... Good luck..

The chemical composition and binding energy states of the deposited thin film can be investigated by XPS. By sputtering etching the sample you know the depth profiles. In addition, the band-offsets (i.e., valence band discontinuity and conduction discontinuity ) at the heterojunctions also measured using XPS, which is important in the fabrication of solar cells.

Dear Colleague Burlu,

X-Ray photoelectron spectroscopy, XPS was used to investigate the chemistry at the surface of the samples. The basic mechanism behind an XPS instrument is that  the photons of a specific energy are used to excite the electronic states of atoms at and just below the surface of the sample.

There are several areas suited to measurement by XPS:

1. Elemental composition

2. Empirical formula determination

3. Chemical state

4. Electronic state

5. Binding energy

6. Layer thickness in the upper portion of surfaces

XPS has many advantages, such as  it is is good for identifying all but two elements, identifying the chemical state on surfaces, and is good with quantitative analysis. XPS is capable of detecting the difference in chemical state between samples. XPS is also able to differentiate between oxidations states of molecules.

XPS  has also some limitations, for instance, samples for XPS must be compatible with the ultra high vacuum environment.  XPS is limited to measurements of elements having atomic numbers of 3 or greater, making it unable to detect hydrogen or helium. XPS spectra also take a long time to obtain. The use of a monochromator can also reduce the time per experiment. 

Hope this helping

Have a very good day