I got depth profile of TiO2 film with SIMS. Some species: TiO- and O- got straight-line distribution throughout the films, while others: C- and H- got declining distribution from the top of the film. Is there any experimental/instrumental explanation to the phenomenon?
We use ToF-SIMS analysis was carried out on an ION-TOF ToFSIMS IV(M¨unster, Germany). Analysis was performed with a 25 keV Ga+
primary ion source . Negative secondary ions flying through a reflectron mass spectrometer were detected with a microchannel plate assembly operating at 10 kV post-acceleration.
Do I understand it correctly: on the top of the film you observe C and H while these vanish in the deeper layers, right?
I'd say that's rather straightforward: in the top layers you probably have hydroxyl groups terminating open TiO-valences which explains the hydrogen.
Concerning the C: do you observe only C or also CO? If you also have the latter, you might have some residual gas adsorbed on the film; otherwise, there might be some hydrocarbons on top.
Dear Jürgen Weippert,
We doped TiO2 with hydrogen and saw excessive concentration of H in the first 100 nm and we skipped the first few nm of the surface in the etching spectrum due to species absorbed .
OK, the hydrogen doping was an important point here. Of course I don't know your method; if you took existing TiO2 and doped it, you probably just determined the penetration depth of your method which might be a number people can be interested in.
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